Arthur Downing, a 73-year-old water park expert who has worked on major resort schemes overseas, alleges his family company spent six years finding the rural site on Steve Irwin Way at Glenview, getting it rezoned for tourism development and preparing a masterplan for a resort attraction, only to be cheated out of the deal.

At the heart of the dispute are a couple of flimsy horse sheds, long removed, that happened to be in slightly the wrong place.

The cases cast a shadow over the park, now in the hands of Sanad Capital, an 18-month-old Sunshine Coast-based outfit led by former professional golfer Bradley Sutherland and his brother Gregory and backed by Dubai-based Najibi General Trading Company.

Sunshine Coast Council has approved stage one of the development, a $90 million-plus water park situated 10 kilometres from Australia Zoo and boasting waterslides, kayaking and bungee jumping.

Mr Downing claims the scheme's new backers exploited a boundary issue created by the horse sheds to hold up the land sale just long enough to avoid paying him an agreed $1.25 million fee for finding and rezoning the site.

Mr Downing also alleges that Sanad's chief operating officer, David Baird, misrepresented himself by failing to reveal his relationship with the Sutherlands while he was supposed to be working to raise money for Mr Downing.

The characters

Born in Ipswich in 1971, Mr Sutherland moved to Dubai more than 20 years ago and worked as a professional golfer before moving into resort development and shopping centre management. In the mid-2000s he was involved in a plan to develop a Dubai golf resort with a course designed by Tiger Woods. The scheme later collapsed and was taken over by another company. He later worked for the Dubai-based Najibi group, the main backer of the water park scheme.

Mr Baird ran a Sunshine Coast painting company and developed residential property before working for UK-Australian mining company Astra Resources. On his Linkedin page he describes himself as a "self-made millionaire by 30 years of age". In 2015 he was named in a Federal Court judgment as one of nine brokers for Astra, which was found to have sold shares to hundreds of investors illegally. Three Astra Resources directors were banned from managing corporations but no action was taken against the brokers. Sanad Capital's website describes him as a co-founder of the company, which was set up in late 2015 at the same time as the acquisition of the Glenview site.

Mr Downing joined the Merchant Navy after leaving school in northern England in the early 1960s. He met his Australian wife while skippering small freighters and motor yachts in the Pacific and moved to Australia in the 1970s. He then spent 30 years in overseas tourism development and was involved in developing water park schemes in Malaysia, Bahrain and the United Arab Emirates through his family consulting company, Waterplay.

The vendor
Sunshine Coast landowner Luigi Venturiello bought the 24 hectare site in 1992 for $40,000 and at one time planned to build a trucking hub on the site. Mr Venturiello died in 2016: his two daughters handled the $3.7 million sale to Sanad-linked company Nurrowin.

'You can't trust the guy'

Mr Baird initially raised seed funding for Mr Downing by selling $240,000-worth of shares in Mr Downing's company Sunshine Surf Park to local investors including champion surfer Julian Wilson.

But the relationship soured.

In an email exchange between Mr Baird and Bradley Sutherland in July 2015, five months before the Glenview land sale, Mr Baird said of Mr Downing that "you can't trust the guy" and described plans to "bankrupt" him.

He later successfully sued Mr Downing for $165,000 in payment for his role.

"When we file this case and it gets pressed it will derail the planned project and no-one would invest a penny into it after that and the council will probably pull the approval," Mr Baird told Mr Sutherland.

"Personally I don't really care, I've moved on, myself and the investors will bankrupt Arthur and his wife over this you have my word; he thinks I can't and/or won't, so he's in for a rude shock."

The horse sheds at the centre of it all

The deal to acquire the land for the park was due to be finalised in December 2015 when the sheds were discovered on the premises.

Correspondence from that time shows Sanad, citing the boundary problem with the horse sheds, negotiated a new deal with the landowners in which they bought a small block on the other side of the proposed boundary in addition to the main 24-hectare site intended for the water park, for a total of $3.7 million.

The landowners were told the deal must settle nine days later, on Christmas Eve, 2015 - one day too late for Mr Downing to get paid under his original agreement.

"There's no reason why, even with all that, that they couldn't have settled on December 23," Mr Downing said.

The sheds were removed once the land had changed hands.

"You could have taken a 28-pound hammer and knocked them down in 10 minutes," Mr Downing said.

One of three court cases

Mr Downing and his company Australia Pacific Investment have filed a claim in the Supreme Court in Brisbane claiming to be the victim of misleading and deceptive conduct on the part of Dubai-backed Najibi General Trading Company, its Australian arm Nurrowin, which bought the site, and Bradley Sutherland, a director and co-owner of Nurrowin.

The defendants have denied the allegations.

Mr Downing also claims Mr Sutherland promised him in writing that he would pay the original investors and Mr Baird at the same time Mr Downing was to receive his $1.25 million fee.

But the investors were never paid, and are now suing Mr Downing.

Fairfax Media has obtained a copy of an email from Mr Sutherland to Mr Downing sent on September 4, 2015 in which Mr Sutherland wrote that while he was unable to include it in a legal deed covering the deal, "I can assure you (and please do take this as an undertaking from us), that ... on completion, we will pay you the SSP and David Baird settlement costs".

The District Court earlier this year ordered Mr Downing to pay the investors, but he has lodged an appeal.

"We only signed the deed because of assurances from Bradley Sutherland that he would pay (the investors and Mr Baird) and he has scallywagged his way out of this," Mr Downing said.

Questions raised over park's future

Mr Downing said he had reason to doubt the claims being made by the new developers in their marketing material for the scheme.

"It's still a paddock and I think it will stay a paddock. If they've got $400 million, then, as they say in Yorkshire, my arse is a cream bun."

Sunshine Coast Council said it was "aware that there are legal proceedings under way that are connected with this project and will not speculate on outcomes or ramifications".

Representatives of Sanad Capital declined to answer Fairfax Media questions.

The lawsuits

February 2016
David Baird sues Arthur Downing in the District Court in Brisbane for $165,000 he claimed he was owed for raising investment capital to get the water park scheme off the ground. Mr Downing later resolves the case by paying Mr Baird.

May 2016
Arthur Downing and his company Australia Pacific Investments file a claim in the Supreme Court in Brisbane against Najibi General Trading Company LLC, Nurrowin Pty Ltd and Bradley Sutherland, alleging misleading and deceptive conduct, breach of trust and breach of fiduciary duty. The defendants file a defence denying all the allegations.

September 2016
Investors in companies Mr Downing set up to develop the water park, including surfer Julian Wilson's company MNSBJ Pty Ltd, file a damages claim in the District Court in Brisbane over payments the allege they are owed for their shares. The judge rules in their favour.

April 2017
Arthur Downing files an application in the Brisbane Court of Appeal for leave to appeal against the District Court judgment over the investors' shares.