I used to help Gary on the early spot, not sure if I'm the Sean you're referring to or if there was another guy playing later. Gary had been looking for people with a few records who could do a spot, and whilst I had some good records from soul packs and junk shops, I didn't have the confidence of fronting it! Loved these days - not just the buzz of playing records, but just the fact that new stuff was coming out all the time and not just new releases. Your list of Keb's cover ups gives a great feel of the time - he gave me a tape from a guy called Steve Pullman that just had the most brilliant stuff on it that took years, and even decades to actually hit the scene in a big way.
I wasn't that into the Mod side, but everybody was into the music and Notre Dame was a magical little secret bang in the middle of the city! I remember my sister and her boyfriend coming up one night to stay over, parking optimistically in a side street, getting towed and and us all having to get a cab out to the lockup area, not being able to pay the fine and having to walk from Elephant and Castle (or nearby) back to Woolwich.
I've link to a few flyers from the time and other bits on Flickr.
Sean