I found my copy of Fit Like New York, and there is a whole chapter about Lemon Soul. There's a huge amount of background stuff about the various members and other bands they were in, but the key paragraph about Lemon Soul is this - They only lasted two years, their last gig being the Cowdray Hall in 1968, and as far as I can see they never recorded anything. But apparently in 1993 a chance telephone call by Kevin Henderson from his home in Frankfurt to the Dutch Mill got them all talking again, and a reunion gig came about on April 3rd 1994. It seems this gig was recorded from the mixing desk, but God knows if it still exists anywhere. As I say there's tons more about the whole scene at that time in the book, if you want I can scan the whole chapter for you.