Allen was just 15-years-old at the time, and in 1979, he dropped out of school to concentrate on a career in music full time, which saw him performing on stage, opening for AC/DC on his 16th birthday.
However, these glory days were set to change when a terrible accident saw his life completely change.
On December 31, 1984, Allen and his then-girlfriend Miriam Barendsen were driving on the A57 just outside Sheffield, from which the band hails.
According to Ultimate Classic Rock, Allen misjudged a curve which saw the car crash through a stone wall and flip car several times.
Allen’s seatbelt was not fully fastened, therefore he was ejected from the vehicle.
He told the BBC: “I think my arm was left in the car,” though someone who lived nearby packed his arm in ice, in the hope of reattaching it.
“At first even walking was a trial, but I locked myself away in a room at my parents’ house in Dronfield and just played and played.
“There were times when I thought I just couldn’t do it and wanted to curl up into a ball and give up. But I persevered.
Allen continued to practise on a specially designed electric kit, often in a separate studio to his bandmates, who at no point sought a full-time replacement for him.
From then on, he performed as their only drummer, making a triumphant return at Monsters of Rock, a festival in 1986.
While Allen has openly spoken about the darker side of his recovering, which included self-medicating and PTSD, he also hopes to try and help those who are suffering in similar ways to him.
Speaking to ABC News in 2012, he added: “I didn’t know what my life would be like after that terrible day. It was the darkest time in my life…
“My desire is to encourage a support system for warriors, de-stigmatize PTSD, share their stories and offers alternative ways to pave the road to resiliency and health.”