In TSP, she references at one point that he was a 'trained master plasterer' and that plastering was a skill he'd returned to many times during his life. That to me suggests he'd worked in construction, but not necessarily in any sustained way.
She describes her own employment history as follows (this is the part of TSP where they are staying over winter in Polly's outbuilding in exchange for renovating it):
And who wants a fifty-year-old woman whose work history for the last twenty years has been self-employment? It didn’t count that I’d been a farmer, plumber, builder, electrician, gardener, decorator, designer, accountant, tree surgeon, and run a holiday let. I had neither a piece of paper or an ex-employer to prove it. I would have to retrain. But even then, who would want to employ a fifty-year-old newly qualified woman when they could have the equivalent twenty-three-year-old?
She seems to suggest in this whole episode where she represents herself as trying to find work and somewhere to rent (impossible because we 'dragged our credit history wherever we went') that they'd both worked largely on their farm for the previous twenty years, only it's never clear to me whether they were actually farmers in any real sense, or just kept a few animals and hens so that they could describe the barn they rented to tourists as a 'farmstay'?