A couple of years ago, Michael Soffe seemed to have a charmed life. A gourmet tour guide and wedding planner, he’d made a home and built a business in sun-soaked Málaga, the increasingly hip city at the heart of Spain’s southern coast.

Now he fears that everything he’s worked for is hanging in the balance as heedless politicians push Brexit negotiations to the brink. His biggest worry is that his partner, a two-time cancer survivor still in treatment, could lose his right to public healthcare.

“We are petrified that will be taken away,” Soffe said. “There is not a single insurance company that will touch him.”

There is also his pension. Having spent more than 30 years living in Spain, the savings that he was relying on to retire in a few years’ time would be much reduced if EU agreements to share welfare credits earned in different countries were abandoned, he said.

His business, at least, should be resilient, Soffe said, as he tried to escape the long shadow cast by Brexit at an anniversary celebration in one of Málaga’s most garlanded tapas bars, KGB. “We don’t rely too much on British visitors, thankfully.”

Pension and healthcare worries loom large among British immigrants in Spain, particularly those clustered on the coast. The cliche of Costa del Sol life is played out in many small settlements where older Britons enjoy a sun-filled version of retirement in seaside towns, with breakfast menus featuring fry-ups instead of tortillas, and no Spanish required.

But they are actually a minority of nearly 300,000 UK citizens formally registered to live in Spain. Two-thirds of that group are working, said John Moffett, vice-chair of the campaign group Bremain in Spain, which is pushing to protect their rights.

They face a tangle of questions, not just about Britons’ right to live and work in Spain and other EU countries, but their entitlement to benefits, and whether their qualifications will still be recognised. For those with children, there is the question of what the long-term prospects might be for young people.

Tour guide and wedding planner Michael Soffe has lived in Spain for more than 30 years. Photograph: Emma Graham-Harrison/The Observer

Many of those grappling with the implications of Brexit say they feel their concerns have been forgotten by politicians, and their lives used as political pawns.

“I’ve never been a good sleeper, and I now have the radio on all night. I’m waking up in the early hours, putting the lights on, getting my glasses on so I can check if there is any news on Brexit,” said Alison Curtis, who has been living in Spain for three years.

She has a daughter and grandchildren living there, too, and never wants to return to Britain. But, as a cancer survivor, she feels she can’t stay on without guaranteed medical care. “I would definitely have to go back if I can’t get healthcare, as my situation is not going to get better.”

Large numbers of Britons in countries including Germany, France and Italy have swept away many of the questions about work, pensions and healthcare by applying for a new passport. But it is a more fraught option in Spain, because Madrid does not generally allow dual nationality. So, to become Spanish, people have to give up their British passports.

For many, that is a step too far. Valerie Lawrence is one of those who has decided to go ahead, “for purely emotional reasons”, and despite serious worries. “I don’t know if it’s a sensible idea, because I am dependent on UK healthcare and a pension,” she said. “Could these be withheld from foreigners in a post-Brexit future? We are all scared and paranoid now.”

Not everyone is so gloomy, though. Dilip Kuner, editor of the English-language free paper Euro Weekly News, based in Fuengirola, says anecdotal evidence suggests that the division in attitudes to Brexit along the Costa del Sol is not much different from back home in the UK.

“From our postbag, I’d say it’s pretty evenly split,” he said, speaking in the office of the paper, which runs a weekly page of Brexit news. “[The overall divide] was very much reflected here among the expat community, which I found surprising. I thought it would be very much more a Remain vibe.”

Robert Joseph Lewis has spent more than 15 years in Spain. He is still working because his pension doesn’t stretch far enough, so further cuts would bite. At nearly 70, he expects to need medical help in future and can’t imagine trying to move back. “There’s nothing in the UK for us,” he said.

But Lewis is a firm supporter of Brexit, angry that the process has been dragging on for two years and frustrated with Theresa May. “She’s not the right woman for the job, a Remainer trying to drag us out, its crazy.”

Like many others in the region, he is convinced that Britons in Spain bring too much financially to the country – and save the NHS too much in care costs – to force pensioners like him home. “It doesn’t worry me, there’s a lot of scaremongering. Just a lot of ‘what ifs’. There’s no way they will throw us out.”

Alan Stead, a 67-year-old from Halifax, is also fed up. “It’s project fear. I don’t believe any of it,” he said of warnings about a no-deal Brexit, as he finished a Spanish class at the Los Amigos bar and social club.

He owns a holiday home, and comes with his wife for just a few months a year in winter. Permanent residents dismiss visitors like the Steads as “swallows” with far less at stake, because their UK base means their healthcare and pension are safe. “For people like us, I don’t think anything is going to change at all,” he said. “If Spain expels all the British expats, the economy will tank.”

As at home, there are also people who have given up following the convoluted politics of Brexit. Sharon moved to Fuengirola eight months ago, deciding it was “now or never” to start a life in Spain, and bought the popular expat hangout Aidan’s Bar.

She relies on foreign customers, and EU rules that allow her to run the business. But efforts to implement the referendum are so chaotic, she isn’t even following them. “What will be, will be,” she said, on a patio overlooking a fountain. “I don’t think even [the politicians] know what they are doing, so how can we know where things are going?”