This had its genesis at a pub in the Cathedral City of Wells, where I thought the daily special - usually a good bet - of roast beef with Yorkshire pud and roast potatoes sounded rather nice whereas my wife opted for a pork sirloin with some sort of fancy sauce.
The roast was not quite awful but it had probably been taken from a packet, was definitely pre-cooked and warmed up, and the meat was short on taste and fairly tough. However, the pork sirloin was excellent.
Musing on this I realised that my mistake was to opt for a meal that could be pre-cooked and warmed up in a microwave. In future, it was decided, I would stick to food that pretty much had to be cooked fresh.
Taking that as a guide we thereafter opted for dishes like sausages and mash, fish and chips (in places like Boscastle and Marazion where there was a good chance of the fish being fresh), lamb souvlaki and (in Piraeus and Clovino Beach) grilled sea bass and calamari.
We did also try a few things like moussaka, lasagne and steak and kidney pud (which I adore) likely to be pre-cooked but which shouldn't be ruined by re-heating ... and - with the exception of the first steak and kidney pud in a pub in Oxfordshire - we were right.
So if you want to eat well in a strange town my advice is: look for where the locals eat or ask advice from a local, consider the daily specials and where possible choose dishes that have to be freshly cooked. Happy eating.