The album is called "Steve Harley and Cockney Rebel - The Collection" and was a double LP in 'The Collectors Series" published by Castle Communications in 1988 - their reference number was CCSLP 197
Their address in case it is still live/still helps was Castle Communications PLC, Unit 7, Merton Road, London SW18 5JS
Several of the tracks on side 3 and 4 were live including Mr Soft
If you can't get hold of a copy via the originators then try Netsounds.com (
www.netsounds.com) a secondhand web warehouse that brings together all the second hand offerings in the UK, Europe and beyond.
Good luck in tracking down a copy