When did fresh produce come to be available year round in the Isles?
There was a tradition of growing in orangeries and greenhouses dating back to Elizabethan times in England but at that time it was the preserve of the aristocracy. However it took off big time in the Victorian era so it wouldn't be that unusual to be served fresh cucumber and tomato for your afternoon tea sandwiches out of season especially if your host had a garden. But the amount that people could grow in their own domestic greenhouses was obviously limited so it was still a 'treat', not a daily thing. People still did a lot of pickling and preserving though just as Poles still do today. The1960s really changed everything with most people getting a fridge and the advent of frozen food. Then of course in the 1970s with the EEC you saw a lot of importing of fruits and veggies from other places so the 'season' for strawberries for example became earlier. The same thing is happening in Poland now.
My husband would eat them with zsiadłe mleko and koperek.
"historical food trauma
There could be something in it though. Most Polish posters here aren't old enough to remember those times but Mr Atch does. He was only a kid but he remembers going to the shop for something one day and there was nothing there except vinegar, wall to wall vinegar!
stigmatized in terms of their culinary talents
Have you read the diary of Parson Woodforde?? You'd love it! He lived in the 18th century, died in the early 1800s. It gives a very good account of the food of the period in a middle class household as he recorded what was served for dinner each day. You might be surprised. Here's an example:"We had for dinner some Pike, a Couple of Fowls boiled and Piggs Face, green Peas Soup and a prodigious fine and fat Haunch of Venison ... The second Course was a Fricasse, a Couple of Ducks roasted, green Peas, plumb Pudding, Maccaroni, &c. ..."
I always remember one quote in particular from a Christmas entry when he didn't sleep well as 'mince pie rose oft' during the night :D