Was it Opportunity Knocks? I seem to remember something from years ago but I think it was a quiz type thing, though I'm pretty sure Hughie Green (or Michael Miles) was the host. Maybe 'Open The Box' or something like that. I remember he came back for several weeks winning increasing amounts of money and for some reason I still remember him correctly answering a 'trick' question about The Matthews final of 1953, namely which Stanley scored a hattrick?
money
http://news.bbc.co.uk/sport1/hi/in_depth/2000/ wembley/936013.stm
I don't know if this is the same guy or not, but your question sparked a few memories from a long time ago.