Hallo Diane/Northerner... Unfortunately I don't go to the Topic myself much as I live in Somerset; I do the website long-distance for my brother John, who is act booker and occasional MC (and floor singer) there. He's at the university; in the early 70s he was a research student and lecturer in the then Dept of Yugoslav Studies, and now he goes to China and the Gulf to grab overseas students. But he didn't go to the Topic much then - there was a Uni folk club, though it was quite traditional and sniffed at him showing up with a guitar. He spent more time at the Bradford Playhouse (and Film Theatre)(now the Priestley) in the 70s and 80s.
I don't know how many people at the Topic now were there in your day. Roger Sutcliffe, a former club organiser, goes - he has performed nearly every year since 1964. Trevor Charnock, also a former organiser from the 70s and 80s, goes from time to time.
In your time the club was at the Star Hotel (1969-1991). Now (since January this year) it is at the Cock & Bottle (old pub across the road from the Old Paper Hall, Bradford's oldest building, just up from the cathedral). If you look on the website (links in my previous post) you'll see there's a gig list that is (almost) complete from 1970 to now... if you are so minded, you could probably pin down some of the evenings you sang if you could remember the headline act. For instance, 5th Jan 1973 was Martin Carthy, 7th June 1974 was Vin Garbutt, 7th November 1975 was the 19th Anniversary Weekend with Roy Bailey and Leon Rosselson.
It is the 50th anniversary year of the Topic now!