As for payment; we only ever pay by cheque/BACS for ‘big’ jobs, as we need a traceable transaction for our own tax/insurance etc. For small jobs, we might pay cash. As for trades people declaring their earnings etc; if a flash git turns up in a shiny new pickup truck, demanding cash only, he can jog on. If he’s come on the bus, with his tatty toolbox strapped to a shopping trolly, and is struggling to get by, then I couldn’t give a toss if he’s ‘fiddling’ his tax, good luck to him. I might even give him a few quid more on top. But generaly, we’ve actually found that the best people don’t actually charge much, clean up after themselves properly, and are always 100% above board on everything.