At the end of a quiet, unassuming cul-de-sac, a steep hike from the centre of Bath, there is little giveaway of the dual Olympic ambition that has long absorbed the occupants of the last apartment on the street. But for those in the know, the signs are there: the vast number of trainers overwhelming the shoe rack outside the front door, the massage gun discarded on the sofa, the photograph on the window ledge showing two people beaming at the red-carpet premiere of the James Bond film No Time to Die.

The harsh, unforgiving world of elite sport is not a particularly welcoming place to find a fellow partner. Common ground located in shared aspirations can easily be lost in the cut-throat reality of individual success and failure. Joe Choong and Liv Green know that all too well.

Their presence at that London film premiere came courtesy of the Olympic modern pentathlon gold medal Choong had won a couple of months earlier. So, too, when they travelled to Paris this year as guest diners at the final banquet for Great British Menu. “Being his plus-one has got me to some really cool events,” says Green. “I’ve bunny-hopped along.”

The hope was – and, just about, still is – that she can shed the plus-one tag at the Olympics next month. While the 29-year-old heads to Paris as the man to beat after adding successive world titles to his Olympic crown, Green claimed a European Games bronze of her own last summer.

Britain’s pentathlon power couple – whose sport combines fencing, swimming, showjumping, running and shooting – seemed on track to realise their dream of competing together in the French capital. But with Green experiencing a dip in results at just the wrong time, the 24-year-old’s hopes are dwindling of gaining one of the two spots in a British women’s team that possesses unparalleled depth. Barring a remarkable performance at the world championships that began in China on Saturday, she is likely to miss out.

“Hopefully, it doesn’t go that way,” she says, cradling a cup of tea in their kitchen. “I would be really disappointed but it happens so I’d just have to deal with it. I’ll just be happy to watch Joe compete and try to support him as best I can.”

That support – so often unseen – has been taken to extremes in the past. For the Covid-delayed Tokyo Games, held in 2021, Green sacrificed much of her life to help ensure her boyfriend’s health for a period in the buildup.

Suffering a badly sprained ankle and unable to train, Green had the option of enjoying her summer and living as normal a life as the pandemic allowed, which would have meant being unable to see Choong for the risk of giving him Covid. Instead, she hunkered down with her partner.

“It was very hard for me,” she says. “I didn’t really have a life so it wasn’t a pleasant time, but it was worth it to support Joe, and he got his gold medal, which was amazing.”

Over recent weeks, Choong’s support in return has included staying up all night to help a distraught Green craft an ultimately unsuccessful appeal letter after she was not selected for a crucial pre-Olympics competition – a decision that appears to have laid a path to her absence from the British team for Paris.

It is not the ideal backdrop for an Olympic champion to defend their title and Choong admits having the support bubble of his girlfriend in the camp would provide him with the best opportunity of earning a second gold medal. But he laughs at the audacity of ever asking for Green to be selected for his benefit: “I wouldn’t expect that in a million years.”

Results over recent seasons suggest he stands a fair chance of becoming the first British pentathlete to win two Olympic medals. Should that be gold it would doubtless grow his profile far beyond a sport that struggles to puncture the public consciousness.

“I’ve had some nice products and some sponsorship off the back of my gold medal,” says Choong, as Green delves into a cupboard to find some luxury high-performance tea he has been sent. “But I still live in the same house and still drive the same car so it’s not been life-changing like you would imagine.”

There is another reason for Choong’s desire to win gold in Paris; extra motivation to stand atop the podium. This is likely to be the end for him as a pentathlete.

While Choong was realising a lifetime’s goal of Olympic gold, the sport was gathering unwanted attention when a German coach was thrown out of the Games after punching a horse that refused to jump. After that controversy, the sport’s governing body confirmed showjumping would be replaced by Ninja Warrior-style obstacle racing after the Paris Olympics.

Choong has been one of the most outspoken athletes against the move, criticising the decision-making process and arguing that athlete voices were not considered. Instead of attempting to start from scratch in a discipline he has never tried, Choong has suggested he will most likely retire from pentathlon after competing in Paris – a statement that prompted the governing body’s president, Klaus Schormann, to glibly respond: “OK, bye bye.”

Choong, a maths graduate, says: “That was hilarious, really. I can’t imagine many other international sports presidents being so personal. I thought that summed up how he treats the athlete community. It’s an echo chamber in the senior leadership where one of them will have an idea and the rest of them will go for it, rather than getting external expertise.”

Unless Green can force the selectors’ hands at the world championships in China it means their yearning to compete together at an Olympics will never be realised.

For Green, five years her boyfriend’s junior, she hopes there is no end in sight, regardless of whether she makes it to Paris or not. But, like the rest of the pentathlon world, she has no idea whether she possesses the ability to continue in an altered sport. “I definitely will give it a try to see if I enjoy it and if I’m good at it,” she says. “But I’ve never done an obstacle race.”

The future remains clouded in uncertainty and they could have left the much-changed sport by the time the Los Angeles Olympics roll around in four years’ time. Of more immediate concern is the great unknown of Paris and whether Green will be on the ­startline or watching from the stands.

“The biggest problem I’d have is you only get two tickets as an athlete,” says Choong, joking. “So I’d have to choose between Liv and my parents.”