The rambling Syd bits were all scripted by Took and Feldman. Kenneth Williams was the performer. Here's my favourite -

RAMBLING SYD: (SPOKEN) Now my dearios I'll tether my nadgers to a grouting pole for the old grey mare is grunging in the meadow. Well, better there than here—It makes so much work for the char. 'Tis about a fabled horse, the Somerset Nog so called because it's a cross between a nag and a dog. Half Suffolk Punch and half Dachshund. It gets very foggy on the moors. Anyway, the Nog is a strange looking creature — three-hands high and eighteen-foot long. They're not pretty to look at but the rhubarb in that part of the world be magnificent. My song tells of a man who wants to go to the great fair at Ganderpoke Bog — so he asks the farmer for a loan of the Nog, so he can take all his friends with him, and it proceeds in this fashion.
To the tune of Widdecombe Fair

Rambling Syd: (SINGS) Reg Pubes, Reg Pubes Lend inc your great Nog.
Rollock me £ussett and griddle me nodes.
For I want to go~o to Ganderpoke Bog, with —
Len Possetr, Tim Screevy, the Reverend Phipps, Peg Leg Loombucket, Solly Levy. Ginger Epstein. Able Seaman Truefitt, Scotch Lill, Messrs. Cattermole, Mousehabit, Neapthigh and Trusspot Solicitors and Commissioners for Oaths, Father Thunderghast, Fat Alice, Con Mahoney, Yeti Rosencnrnz, Foo Tong Robinson and Uncle Ted Willis an' all - and Uncle Ted Willis and all.

(SPOKEN) So they all get on - except Fat Alice, who don't get on with anybody, and off they go, but sad to relate - the horse snaps in two and expires - but they do say as how its ghost walks abroad - in two halves, and if you be passing Ganderpoke Bog at midnight they say you can hear the two ghostly halves of the Nog singing in duet… RAMBLING SYD: (SINGS)
Reg Pubes, Reg Pubes you lent your great Nog
Rollock me fussett and grindle me nodes, And now my remains are in Ganderpoke Bog — with
(as quick as possible)
Len Possett, Tim Screevy, the Reverend Phipps, Peg Leg Loombucket, Solly Levy, Ginger Epstein, Able Seaman Truefitt, Scotch Lill, Messrs. Cattermole, Mousehabit, Neapthigh and Trusspot Solicitors and Commissioners for Oaths, Father Thunderghast, Fat Alice, Con Mahoney, Yeti Rosencranz, Foo Tong Robinson and Uncle Ted Willis an' all - and Uncle Ted Willis. (First broadcast 6th February 1967)