Sydenham and Lewisham couple testing their relationship by racing the length of South America

You’re leaving the house and realise you have forgotten your wallet. 

You pat your pockets – not there; look on the kitchen table – not there. Where did you leave it?

We’ve all been there. Except that in this case, Michael, from Sydenham, was in Honduras, trying to travel more than 6,000 miles along the length of South America.

For the former soldier, 47 – now a health and safety project manager – and his partner Shuntelle, a project manager, it is a defining moment. 

Ten travellers in five pairs travel across 16 countries from Mexico City to the most southerly city in the world, Ushuaia in Argentina. All without taking a single flight.

Three of the pairs are related to each other, but Michael and Shuntelle, together for three years, are also up against a married couple of five years, Jen and Rob.

And they must do it without the trappings of modern life – no smartphones, internet access or credit cards, and armed with only the cash equivalent of a one-way airfare.

In the first episode, the teams set off from Mexico City – the largest Spanish-speaking city in the world. On their journey, they must pass through seven checkpoints to reach their final destination. 

Shuntelle and Michael were travelling through Honduras on their way to the next checkpoint in Panama City, when they found they had misplaced their cash.

Michael had bought some street food – and minutes later realised he’d lost his money belt, containing more than half of the pair’s remaining budget for the entire race.

A panicking Michael went back to the street food stall, a bus he’d just jumped off and anywhere else he could think of. The search used up valuable time, threatening the team’s position in the race.

Ex-army PT instructor Michael has always a hankering for adventure. “I joined the military when I was young,” he said. “It gives you that confidence.”

Shuntelle, though, likes luxury all-inclusive travel. There were “differences of opinion” – ie rows – early on over accommodation.

Shuntelle and Michael met on Tinder three years ago but are yet to take the plunge and move in together. The race was a huge test to their relationship – the longest time they’d spent together.

Shuntelle said: “I am 40 and have been sensible all my life. I’ve always made the right choices and never taken any major risks. I’ve entered a new stage in my life and I feel I wanted more. It’s time to move away from the all-inclusive holidays in Jamaica and see what else the world has to offer. I also want to show my boyfriend that I am not made out of cotton wool.

“Surprisingly I expected to miss the phone more than I did. Obviously, it would have been great for being able to get around, get to the buses, understand timetables and to work out where to go but not for social media and being contactable. I enjoyed being off the grid.”

Michael said: “We entered to win the competition by doing something that I like to do. We also saw it as a test of our relationship and how we get along with each other.

“I was so focused on what we were doing that I didn’t miss anything. For me it was all about the adventure.”

The couple are now back – but we won’t find out what happened until the end of the series. 

“I haven’t been recognised in Sydenham yet,” said Michael.

Former Deptford Green pupil Shuntelle added: “I have been recognised at my local gym on Monday night. I drive everywhere so am hiding in the comfort of my car and working from home this week so haven’t been out and about much.”

Race Across the World is on again on BBC2 at 8pm on Sunday.