Thanks for some responses!

Frug: Dave and Toni Arthur have already been eliminated (well, probably) by Dave Arthur himself.

GUEST: Google must index Mudcat quickly or frequently, as the top result using the search string:

"tony irvine" dave sheffield

is your response to this query! But that looks like the right result on The Broadside, so thanks for that. John Conolly still comes to The Topic, 2008 his most recent appearance.

flush: Thanks. The BACCApipes pic I linked to above had Liz Narey from the club, and Paul Kean, and "Steve, Ken and Andy", so presumably they had some personnel changes. Again, searching for Big John Marshall and Charles Parkinson on Google gets you this Mudcat thread as the top result!

(Unfortunately, searching for "Big John Marshall" alone gets you to a marginally NSFW blow-up doll by that name, I kid you not! But I see from more subtle searching that the real John Marshall was from Ilkley).

Dave Sutherland: John Freshwater could have been an American on tour. There seem to have been quite a few in the early days of The Topic, including Joe and Eddie. There were unproven legends that both Paul Simon and Bob Dylan showed up at one time or another as floor singers.

Les in Chorlton: actually, I didn't have a link to New Heritage or their members on our Contacts and Links page, so now I can add that, thanks.

There are 510+ links on that page, many probably now broken... time I went through again and updated it.