Richard, when I contacted Stationer's Hall a few years ago to try to register a copyright, they told me (on the phone) that they no longer provided this service. I don't know what the situation is with registering patents there - if any - but I think the only way one can now register a copyright is the good old send-it-to-yourself-via-registered-post route (and the PO sez: don't tape the envelope flap down).

I fully agree with you that this guy should be challenged with a letter querying his actions. He sounds unscrupulous, has obviously caused a lot of anxiety, and should be given a dose of his own medicine. Your sample letter (and everything else you wrote) is excellent and helpful. I hope Graham will follow your advice and then let us all know how it turned out.