a 2,500km charity bike ride through the Baltic states was jeopardised by a manic search for a spanner.
Gareth Sell's attempt only started thanks to a Finnish hotel owner who found a replacement for the tool he had forgotten to bring with him.
The discovery of a spanner enabled Mr Sell to fit the pedals he had removed from his bike to get it on his plane from the UK.
Earlier this year, Mr Sell's charity hike around Australia almost ended in disaster when he passed out in the Western Desert and was nearly killed by a road train.
Less than six months after returning to Essex from that ill-fated challenge for Help for Heroes, the former soldier cycled from the Finnish city of Jyväskylä to the UK in two weeks – riding up to 230km a day.
Starting on August 4, Gareth cycled through Estonia, Latvia, Lithuania, Poland, Germany and Belgium before reaching the UK.
Now a cable engineer for BT, the 30-year-old from Pilgrims Hatch threw a dart at a huge map of Europe to decide the starting point for his mammoth trip to raise money for Barnardo's, a children's charity that looked after his mother when she was young.
The Scout leader said: "The drama started on the first day. I'd taken the pedals off so I could transport my bike better but I'd forgotten to bring the spanner.
"While I was cycling through Lithuania I was thinking that I must be crazy doing it.
"Anyway, there was this guy who was encouraging me and pulled into a lay-by where he dug around and gave me two silver coins and told me good luck.
"It was random acts like this that made it all worth it and kept me going."
After making good progress on the first few days, he arrived in Berlin on day seven.
He said: "It was hard in the beginning but after Berlin all the aches and pains went away.
"But after that I was in this huge forest and I just thought of all those who died in the war. It was quite a big moment for me."
Mr Sell eventually arrived back in Brentwood on August 17.
"I've raised about £200 so far but I hope that will go up," he added. Visit uk.virginmoneygiving.com/garethsell
