"Perhaps we can agree that we find a mixture of 'hooey' and well-documented research in the work of Copper? Nothing to say that people cannot or do not produce both."

I suggest you wait until you've actually read the work of 'Copper' (ugh) before making a pronouncement like this, and expecting anyone to agree to it.

"When I read the Vic Smith interview, I was reminded in part of those TV programmes where a guest has a product just on the market and this inevitably is mentioned during the programme. Nothing wrong with this, and it doesn't not imply that the product is poor quality."

We're not talking about quality here. You've brought up an allegation of 'bias', which suggests you believe that Bob Copper's account of life and singing culture in Rottingdean may be unreliable. I'd like to know how you can justify this, on the basis apparently of a single interview, albeit one which includes a wealth of extremely important detail.

"A lot of modern folk singers and musicians are professional or semi-professional, as indeed is Brian himself. The Coppers seem to fall into this category."

The Coppers run a very attractive website these days, not surprisingly since certain family members are professional graphic designers. Of course the family has been paid for their guest appearances, but again I don't see how this bears on the accuracy of Bob Copper's testimony in 1971, which is what we are talking about.