Lots of actors and actresses near the end of their careers have had roles in Colombo. I guess some at the start of their careers have had roles there too. I wouldn't recognise Stuart Damon if I saw him.
I tell a lie. I did watch the Champions but had forgotten it.
English actors chancing their arm in Hollywood would probably have been glad of a small role in Colombo or the like.
I can say, with hand on heart, that I've never seen an episode of General Hospital. I couldn't have been paying much attention to The Champions if I didn't notice that Stuart Demon spoke with an American accent.