Thanks for the thoughts sandra in sydney & JennyO.
I had hoped to avoid doing that, as I know John & Nicole are on their tour of the UK at present, and I didn't want to bother them. However, I may catch up with him at one of their gigs ...
I have a tune in my mind anyway but, occasionally in the past when I have learned a new song in this way, I have (slightly) mis-remembered the tune - which can be embarassing! So now I don't trust myself!
"They've poisoned the oceans ...!"