I use curry powder to make curried chicken-and-chickpeas on occasion. I have used whole spices in that past, but for one person, that becomes highly cost-ineffective.

The generic term "curry" implies that the contents were simmered in a broth (or gravy, if you prefer) containing the main ingredients of curry powder. I add a ton of fresh garlic, fresh ginger, cinnamon sticks, and chili to mine.

I'm assuming that in the U. K. the expression "going out for (or taking away) curry" means South Asian food in general?

As a digression, the first time I went to a Sri Lankan joint in NYC, I was a bit flummoxed by "deviled beef", which does not come from an Underwood can!