Just found this fascinating thread.

Now Rap-a-tap-tap I learnt from peers who worked on the farms in Cornwall in the mid 1960s - that's the "Master went to market" version (there are several Rap-a-tap-tap songs of course, with the knocking "replacing" an imagined word).
The Dog's Meeting, on the other hand, I learnt from Mervyn Vincent around the same time - to Mervy'n own variation of The Church's One Foundation/Karno's Army. On one occasion, singing it out at a gig in Kent, we were told by an elderly member of the audience that his Grandfather used to sing it - and working the dates backwards we got to the 1890s!

Just for the record, Mervyn's text went:

Now the dog's once had a meeting, they came from near and far,
Some they came by aeroplane and some by motor car,
And when they got to the meeting house they had to sign a book
And each one hung his backside on the nearest hook.

Now they went into that meeting-house, every mother, son and sire,
No sooner had they got inside some bugger shouted "Fire!"
Out they came all in a rush - they had no time to look
And each one grabbed a backside from the nearest hook.

They got their backsides all mixed up which made them very sore,
For no-one had the same backside that they had had before,
And that's the reason why a dog will leave a bone
And go and sniff another dog's arse to see if it's his own.

I've heard it sung using 'arse' and 'arsehole' all the way through - it's much more effective to save it for the last line!

Tom