Colin,
I've looked at Spotify and then Amazon as I should have at the start.
CDs are available with melly on his own and with Mulligan, Digby Fairweather and John Chilton.
With Mulligan there is:
"Meet Mick Mulligan and George Melly" 2nd hand only
"Goodtime George" £3.49 from Amazon UK (also download at same price)
"Ravers" download only at £6.99
"Live Mick Mulligan and his Jazz Band" Buy from Amazon UK £10.99
"The Pye Jazz Anthology" New and 2ndhand from Amazon UK (With Mulligan and Chilton
The download options are probably your best immediate bet.
If you want more about Melly with Fairweather and Chilton let me know
Cheers John