I really cannot answer this with the breadth your question deserves, but I have a few pieces of information about English food around 1800 that might be relevant. One is that city-dwellers often did have dairy that we would probably consider less-than-fresh by today's standards. I believe it was in this book that I read about the difference in freshness between food in cities and rural areas. Lack of refrigeration and dairy herds that were located outside the city caused milk prices to go up and milk quality to go down. Some merchants watered down their milk to increase their profits. As an illustration of this, in Jane Austen's "Mansfield Park," the protagonist is visiting her family in a poor area of a city and complains about the milk being "a mixture of motes floating in clear blue." The character was uncomfortable drinking the milk because she lived in her uncle's rural estate and was used to fresh milk.

As for food, what modern people consider delicious, bland or disgusting varies so much that it's hard to say. But we do have some recipes from the past, and personally I can say some of them seem very unappealing to me, but some sound perfectly tasty. One famous soup from England in the 18th century was white soup, which was popular with the wealthier classes. I've seen several different recipes for it, but they all involve ground almonds that are boiled and strained. Many recipes also include broth, cream and egg. I've also seen recipes for fairly simple meat dishes that wouldn't be too out of place in a modern restaurant but with more variety of wild game than I see in the suburban U.S. For example, it is possible to get venison and partridge these days, but I don't often pick it up at the grocery store.

Due to my limited knowledge, most of this is just snapshots of what you're interested in, but I did just read a fun NPR article on a related subject. It's not a primary source, but I enjoyed it. It's basically about Western cooking developing to have fewer spices than many other regions. You can find it here.