Notorious Neill is said to be "scundered" after he was told he was no longer welcome at Atlas Gym in the centre of the Co Derry town.
Sources say the convicted drug dealer - who was kitted out in shorts and T-shirt and ready to 'fight the flab' - was turned away on Tuesday.
It's not clear why he was refused entry, but we can reveal Atlas Gym was once owned by 45-year-old drug lord Mark Dunford - described in court as the "mastermind" of a major drugs gang.
After Mark Dunford was caught and jailed for a £900,000 drug haul, the ownership of the gym changed.
Dunford recently served a four-and-a-half year stretch in Maghaberry Prison for his part in a major UK drugs gang after a huge amount of speed was found hidden in an oven in the back of a van.
Atlas Gym was mentioned in court proceedings in 2013 after Dunford, who by then had previous convictions for drugs, went on the run to Spain for over a year before he was eventually arrested.
The court was told Dunford had used the gym, which he took ownership of in 2011, to cover his involvement in the drugs trade, making so much money along the way that he moved to a sprawling mansion.
He'd been caught red-handed with the massive haul of speed in 2012 but as he awaited sentencing in 2015 he fled to Spain after having his bail conditions altered so he could go on holiday.
Ironically that's something else Dunford and 'Skeets' Neill have in common, aside from being convicted drug dealers.
For Skeets infamously had his bail conditions for drug charges altered in 2012 so he could go on a luxury holiday to Egypt.
He even brazenly posted holiday snaps of his trip online but at least Skeets returned home to face the hmusic, unlike Dunford who only came back when he was arrested by Spanish police.
One regular gym user told the
Sunday World: "Skeets was all kitted out and ready to get fit but he was told he was barred by a woman at reception. Fair play, he didn't put up a fight or cause a scene - he just trudged off like he was a naughty schoolboy.
"In fairness he really needed the exercise. He's got a pretty impressive beer belly, probably after all those holidays to Benidorm and Dubai.
"And with Celtic winning the league last week he's been celebrating with a few beers which all add up. Looks like he'll have to fight the flab somewhere else.
"It's some life for him though isn't it? Hasn't worked a day in his life, drives around in a new Audi car which he changes every few months, has at least four holidays a year in the sun and spends his weekends boozing and his mornings at the gym.
"Who says crime doesn't pay?"
Five months ago we revealed Skeets (52) - who's unemployed - had not long returned from a dream holiday to Dubai where he splashed the cash to drive high-end sports cars including a Ferrari.
Skeets was jailed for 20 months in 2013 for his part in smuggling £50,000 worth of drugs from China.
He also had charges related to a seizure of £600,000 worth of cocaine and a firearm dropped against him.
Mark Dunford was jailed on March 1 2017 for four-and-a-half years at Dungannon Crown Court, with a judge telling him he'd serve half the sentence behind bars and half on licence.
The court also made a confiscation order of £90,000 or an additional five years in jail.
His sentencing, along with two other defendants, was the culmination of an intelligence-led operation by detectives from Reactive and Organised Crime Branch into an organised crime group involved in the supply of large quantities of class A and B drugs in the Ballymena and Coleraine areas.
On September 28, 2012, police stopped cars in Ballymena and Coleraine and searched a Transit van parked in Coleraine.
Officers uncovered 20kg of amphetamine and 300g of cocaine in the vehicles and 1,100 ecstasy tablets in the garden of a house in Portglenone.
The estimated potential street value of these class A and B drugs is £893,000 and detectives linked Dunford to the drugs through surveillance of a meeting with dealers in England and analysis of telephone data.
Detective Sergeant Gary Moore, from Reactive and Organised Crime Branch, said of Dunford's sentencing: "Police built a compelling circumstantial case against Dunford. The evidence obtained showed he was directing drugs supply from what he thought was a safe distance.
"He organised a large supply of amphetamine to be brought into Northern Ireland... Dunford believed he was untouchable because, in common parlance, he never got his hands dirty.
"He directed and controlled this criminality from what he believed was a safe distance, using a mobile phone and willing accomplices."