See this Glossary entry for glosses on the various people referenced.
(GF) = Georgie Fame speaks/sings this
Spike Milligan, Peter Sellers, Michael Bentine, Harry Secombe,
Arthur Askey, Tommy Cooper, Norman Wisdom, Frankie Howerd,
Norman Vaughan, Dave Allen,
Max Wall, Max Wall, Max Wall, Max Wall

John Cleese, Terry Gilliam, Michael Palin, Graham Chapman,
Eric Idle, Ministry of Silly Walks, Benny Hill,
Max Wall, Max Wall, Max Wall, Max Wall

Steve Davis, Alex Higgins (GF), Jimmy White, Terry Griffith (GF),
Brian Odgers, Dave Early, Bernie Holland, Richie Buckley,
Max Wall, Max Wall, Max Wall, Max Wall

Spike Milligan, Michael Bentine, Peter Sellers, Harry Secombe,
Harry Worth, Frankie Howerd, Norman Wisdom, Tommy Cooper,
Just Like That!, Benny Hill,
Max Wall, Max Wall, Max Wall, Max Wall

(Transcribed by ear, so corrections are welcome.
Thanks to numerous members of the Van Morrison Mailing List for identifying and correcting these names.