It's kinda weird. This stuff made it into the mountains to some degree, enough that one of my Irish sides of the family has a version of it. Both sides have Irish ancestry, but not the exact same lol.
We don't use curry powder though. It's a spice mix that's first cousin to curry, but lacks some of the typical spices and substitutes others. No fenugreek, cumin, and cardamom is considered optional.
We sub in nutmeg, allspice, paprika, and sometimes a bit of cayenne. Doesn't really taste like you'd expect county captain to if you've ever had it in most places. Tbh, I'd call it a different dish if it weren't for the spices being the only changes to what most people make.
Don't tell anyone in my family, but I'm not fond of ours. I prefer a more standard curry than the curry by way of the islands, which is supposedly how the changes came about. No clue if that's true, but we did have some family down in the Caribbean back a long time ago.
When I make it, I just buy a curry mix. The spice islands mix is just about perfectly balanced imo, so I don't try to replicate it.