No, no response from buyer.  Have just phone eBay again and to summarise.

They explained that because the payment was made (even though it was reversed), the system won't allow me to open an unpaid dispute. So, they have manually refunded the FVF but the item was still showing in my eBay summary as unpaid and eligible for an unpaid item case.

To get rid of this problem, as it will not just go away, I have been told to archive the sale. That way I can't see it in my eBay summary (out of sight, out of mind).  If I had tried to cancel the transaction (which I was reluctant to do), the system would have had a problem with the FVF as it had already been refunded manually.

Questioned about possible negative feedback from the buyer who could still come back, I have been told that eBay would look into any negative feedback left by this buyer as they had not paid for the item nor responded to requests for payment.

eBay still maintain that it was Paypal who reversed the payment.  I hope this is now at an end.