A British French Foreign Legion Gulf War veteran is battling his diabetes, asthma, arthritis and the risk of another heart attack to take on an epic fundraising challenge to raise awareness of PTSD and CPTSD.
After his service, veteran Allen Stokes was homeless for 18 years and developed complex post-traumatic stress disorder (CPTSD).
The symptoms of CPTSD are similar to PTSD, but may also include difficulty in controlling emotions, feelings of shame and guilt, as well as destructive behaviour such as self-harm and substance abuse.
After Allen was helped to find accommodation, ending his time living on the streets, he decided to cycle around Britain to give back. During his travels, he is visiting war memorials to pay respect to those who made the ultimate sacrifice.
So far during his journey, the veteran has slept under tarpaulins and bivvies in woodlands, in shop doorways, car parks, indoor group member houses, bed and breakfasts, hotel gardens, road laybys and a churchyard.
Speaking with Jim Gellatly, a BFBS the Forces Station broadcaster, the veteran explained what is driving him to not give up.
He said: "Me myself, I did 18 years homeless.
"Can't get no support, my PTSD is untreatable – it's CPTSD I've got.
"I've got childhood issues as well.
"I got myself off the street with a bit of help and this is me giving something back."
Cycling on a bike donated by Halfords, Tiny, as he is affectionately known by his friends and supporters, is circumnavigating the UK to raise money, but that's not all.
He said: "It's a lot about PTSD awareness.
"I've met so many veterans whose lives are in the bottom of a bottle.
"It's just not fair, man."
Allen hopes to raise £40,000 for some smaller, perhaps lesser-known military charities that he knows need financial support.
The charities include the Plymouth Warrior Within Project, Outpost Charity, Woody's Lodge, Newport Veterans Hub and Armed Forces and Veterans Breakfast Clubs.
While cycling, Allen is discovering new charities he wants to support with his fundraising, so it is vital he raises as much money as possible.
The French Foreign Legion veteran started his epic challenge in Plymouth last December and has since visited locations such as Land's End, Holyhead, Snowdon, Ben Nevis, The Orkney Islands and John O'Groats.
Now in Scotland, Allen is halfway through his challenge. His next target is Hastings and then along the south coast back to Plymouth.
While Allen is raising money for British military charities, he didn't actually serve in Britain's Armed Forces.
The path towards his military career with the French Foreign Legion was forged from Allen's courage in the face of adversity and a determination to serve.
He said: "My dad didn't want me in the British forces, he didn't want me in the forces, full stop.
"Me grandad was Coldstream Guards in World War Two.
"When he came back, he literally ripped his medals off his chest, threw them in the back garden and built a chicken coop over them and my dad was like, that's it, none of my kids are going into the forces and he wouldn't sign the forms when I was 17."
So, while Allen was banned from joining Britain's Armed Forces by his father, the veteran chose a different route.
He said: "I told him I was going hop-picking in France."
Instead, what he really did was join the French Foreign Legion – one of the world's toughest regiments with a reputation for serving in one of the most challenging environments of any military worldwide.
His time with the French Foreign Legion prepared him for the tough physical challenge of his brutal cycling challenge but Allen says, it's the time he spent living on the streets that means camping wherever he finds himself at the end of the day doesn't faze him.
The veteran has been delighted with the support he receives on social media. He keeps his 3,185 Facebook followers regularly updated with photos and videos from his travels.
However, the encouragement he gets while cycling is something else entirely.
He said: "I'm surprised I haven't caused any accidents, the amount of people that are rubbernecking as they go past me.
"When people bib their horn and wave and whatnot, it boosts your morale, it keeps you going.
"If I'm cycling up a hill and I'm struggling and somebody starts bibbing their horn and cheering it gets me up that hill."
But what keeps Allen focused while he cycles up steep hills in the rain all by himself? How is he motivated during the tough times?
He said: "Good old British determination, I suppose.
"And I made a promise when I started this, a mental promise to myself and to every veteran out there that's suffering on the street and whatnot, that I would complete this and I'll do what I can to help them.
"A lot of people comment on my smile."
He added: "Even if I don't want to smile that day and my PTSD is bad, I'll smile, which means they smile back which gives me a real smile then and a boost as well."
Money can be donated to 'Tiny's GB Cycle Ride' by visiting his GoFundMe page.