Thanks, they seem to have paired off but I think they both males. I could be wrong but the 2 larger ones (Orange one and Black one in the one picture) have been together for about 3-4 years, the other two blackish ones have only just been put into the tank in the past week.
Maybe I'm wanting something to happen too soon and must wait a while.
I have put a piece of tile and a piece of slate in the tank. I am now thinking I have too many other fish in my tank. Guppies, Swords, Mollies, Cory, Pleco and a Red tail black shark. It's a 4ft tank so there is plenty of space for them all but I might move my angels out and give them some peace and a chance to breed.