Best way to cook ribs.......

[KatyMac]

Someone said to boil them before I roast them - but they don't fit in a pan without cutting them up

Could I put them in a covered baking tray with water & 'boil' them that way

Then roast with a lovely marinade

What you suggest sounds fine. You could boil them in your baking tray on the stove top first.

How long would they need to boil for?

I've always slow roasted before; I just wondered about a change

I don't boil either, just chop them up, marinade then roast

tyne-teas.blogspot.co.uk/2014/02/barbecue-marinade.html

this really is the perfect way to cook ribs.. simple but just amazing.. (recipe at the end of the article )

Sweet and sour ribs: yireservation.com/recipes/sweet-and-sour-spareribs/
(I've made this several times, but think it works better if you use slightly less sugar than the recipe indicates)