I mean if you take it seriously we do have plenty of good and interesting food, both in traditional and modern cuisine. Hot spice isn't often a part of it, but there's lots of usage of herbs and milder spices. Laverbread, black pudding, haggis (yes, seriously), Worcestershire sauce, and Cornish herby pasty are all solid examples of very traditional foods that are pretty seasoning-forward without even touching the enormous amount of stuff we picked up from other cultures (like the curries)

That's not to say that we don't frequently earn our terrible culinary reputation. We do. Next to our neighbours like France, Spain, and Italy we just do not have the same level of widespread passion for food, and our habits reflect this. A general lack of adventurousness plagues our palates on a national level

My favourite part of British food is the way it has merged with foreign food, like the curry dishes for example.

That does also mean there aren't any British restaurants since they are usually labelled with the culture that shows there is actual flavour and not the culture famous for eating wartime food in the 21st century...

Well, there's no "British cuisine" per se, but there are British restaurants. For example a pretty famous and influential one. Also, most pubs serve food and those are now pretty much everywhere in the world, that's quite British, isn't it? Dunno the history, but I always associated it with the Brits, maybe I'm wrong.

That the name of their unofficial national dish is in Persian/Hindi also suggets something, but I'm sure I don't know what...

Most "American" foods were brought by immigrants too.