So in Singapore, when you see something served as 'mutton' (which is usually in Indian restaurants), there's a high probablity it will actually be goat. Wet markets that sell fresh mutton are all selling goat meat. I'm trying to think if I've ever seen lamb being sold at these markets and I think I've only ever bought lamb at supermarkets and some specialist butcher shops. Actual sheep mutton - I don't think I've seen that for sale here, mind you I think I'd be hard pressed to find that in the UK...
I've depleted my supply of precooked meat from my freezer so when I get back from my trip I'll be taking a jaunt down to a place we call 'Little India' to stock up on 'mutton' (goat).