"Why should we abandon a word that has had a valid use since 1846 and is still very much in currency in its proper sense?"

That statement could also be made as "Why should we cling to a word that has been in use ONLY since 1846 and has always been controversial about making proper sense?"

"Nobody has even attempted to answer any of the major questions"
I think we have, either you missed our answers or simply ignored them. You do not have to agree, but you should recognize that there is more than one opinion to something that is NOT a "yes" or "no" question.

"how does the 'new folk music' relate to the existing one"
Different community, different time, different technology - same reasons for existence.

"do I have to go and get my 8 volume set of The Greig Duncan Folk Song Collection re-bound"
Of course not, unless you have worn out the cover. That is an excellent collection of folk song.

"where do we go to listen to music we used to know as 'folk'"
Good question. Of course, the places YOU went to listen to 'folk" music was either the source, or a manufactured setting where people mimicked the music that was collected.   The question should be, why are people creating places to listen to the music that YOU knew as "folk"? I'm sure that there are people wondering why there are fewer places to hear any tradition that they grew up with.

"where do I send my PRS cheque (silence again)"
Sounds like a Brit thing and since I have no idea what a PRS cheque is, perhaps I could suggest you make it out to cash and I will send you an address.

"what do we idiots who have been working on folk music now have to identify it as"
The obvious answer is - folk music. With a qualifier as to what "folk music" you are referring to, as I assume you have always done.

"what ARE we going to do about 'folktales'"
Continue to enjoy and share them. I would suggest reading Pete Seeger's book on the subject of storytelling. Best way to carry on the tradition.

"oh - and why does the phrase 'pig-in-a-poke keep creeping into my mind? "
My you have a dirty mind!! :)   

"Who ever claimed that it didn't - the 1954 definition is an international one - It seems to me that - having convinced us of the need for change, you then need to pop across the channel and make a start at convincing all the other eejits "
So many eejits and so little time!    Seriously, there is no need for CHANGE. If you accept the 1954 definition it can be applied to modern times. No one is stealing your tradition. You just need to observe it as a living entity.