Cook’s performances at those Euros were steady rather than spectacular. He did “just enough” to edge each contest and land a place in the -80kg final against arch rival Ramin Azizov of Azerbaijan.
It took a controversial last-second disqualification for him to claim gold, but he had retained his European crown and thought the Olympic place was his.
Cook was so focused that Muhammad’s victory in the -87kg division the evening before had barely registered.
Less than a week later he received the “devastating” news that he was to be the -80kg reserve – Muhammad’s understudy – for the Olympic Games.
The British Olympic Association (BOA) initially refused to ratify Muhammad’s selection and questioned why Cook, who had just reclaimed the world number one ranking, was being overlooked.
At the time Cook’s camp believed his decision to leave the GB Taekwondo set-up must have been a factor, something the selectors and management were at pains to deny.
The bitter battle became headline news for over a month and only ended when the Cooks were told they would need £500,000 to take the case to the High Court, a move that could have cost his parents their home if they had lost.
“We knew in our hearts that we could win, but the risk was too big,” says Cook.
“I want to say though that it was never anything against Lutalo – he took the chance and fair play he went and won Olympic bronze [Muhammad also won silver at Rio 2016]. But looking back, it’s a shame the rules wouldn’t allow us both to go.”
At the time, however, Cook was feeling far from philosophical. He said he had been “cheated” and insisted he would never compete for Britain again while the current management team was in place. He found himself dropped by all of his sponsors.
“After the Games, for about six months I went through a real grieving process – I got fat and was depressed,” he says.
“When I finally snapped out of it I began to rediscover the love for taekwondo again, even if my parents weren’t too happy.
“I think after everything we’d all been through they’d have loved me to go into football, boxing or even UFC and at that time, aged 21, I might have gone for it if there had been a serious offer.”
Cook would return to the taekwondo mat, but true to his word, never again in British colours.
The Isle of Man offered an unorthodox, but immediate way back to the international stage – although it would restrict him to non-Olympic competition.
“Even though I couldn’t represent them at the Olympics I was grateful and I’d almost come to terms with it, thinking that perhaps competing at all the other major events would be enough for me,” he tells BBC Sport.
Then in 2014 came an unexpected twist.
Just hours after securing his third European gold – and the Isle of Man’s first-ever major honour in taekwondo – Cook was ushered into a poorly lit backroom at the host arena in Baku, capital of Azerbaijan. The Moldovan taekwondo president wanted to speak with him.
Two weeks later at a London steak restaurant they met again, and Igor Iuzefovici repeated the offer. He would arrange Moldovan citizenship. There was big money involved. It would open a return to the Olympics.
“It was so surreal, amazing and crazy because I’d gone from being the lowest in my life to being like ‘wow this could be a reality again’ and they offered to pay for everything,” Cook says.
“My parents had taken on all of the financial burden since London and I saw this as a way of paying them back.”
Once word got out that Cook was on the ‘taekwondo transfer market’, rival offers came in. Qatar, the UAE, Kazakhstan and Turkey were soon presenting their own terms to his team.
“It became this bidding war, which was exciting, but I was adamant that I would only choose a country who didn’t have a fighter in my division because I didn’t want to take an opportunity from someone who had grown up there,” Cook says.
The BOA initially declined his bid to be released. But after meeting the fighter and realising his mind was set they reluctantly agreed to his request. In April 2015 he was officially presented with a Moldovan passport.
“This didn’t feel like taekwondo,” says Cook. “The contract said I’d receive around £100,000 if I won Olympic gold. I felt like a footballer who’d just been signed by Manchester United.”