It looks like I'll have to answer my own question re: Jim Dale's parody of 'Rock Island Line'.
No, they didn't include the parody in this BBC programme (at least not in the part I was able to hear on 'Listen Again' before the connection packed it in).
It wasn't a frivolous question. Jim Dale wrote 'Piccadilly Line'in 1957 to cash in on Lonnie Donegan's success with 'RIL'.I would only have been five years old then, so would have been a little young to have been a fan of either Donegan or Dale.
But I loved music from a very early age and grew up with my eldest brother's record collection, featuring loads of Donegan, Buddy Holly, Chuck Berry and Elvis (and later Long John Baldry, Chris Farlowe, Howlin' Wolf, Cyril Davies et al - priceless stuff). And 'Piccadilly Line' was always there with the rest. just as legitimate to me as Donegan's song.
On starting Grammar School in 1963 and talking to fellow prisoners about music I got into one of those massive schoolboy arguments which can rumble on for months, rather like Mudcat threads on homosexuality or anti-smoking legislation.
People would keep insisting that Dale's song was NOT a parody of 'Rock Island Line', was 'nothing like it', was 'completely different'.
Remember that feeling of impotent rage when you know you're right but no one will listen to you?
Of course you do.
However, at least it got us talking about music and we all started collecting records ourselves including, in my case, some dubious quality 45rpm re-issues of Leadbelly 78s, including 'Rock Island Line'.
It is such esoteric stuff which shapes our lives and helps make us what we are.