Hi Guys - just to close this off, I replaced the suspect components with suitably rated ones from Cricklewood and got lights but no music. I left it with a local 'commercial' repair man a week ago and he's just advised he can't find the fault, despite all components (not just the ones I replaced) testing well within spec. I'm going to collect the corpse tomorrow and start shopping for a replacement.
Thanks to all who offered advise to try and get it back up and running.
Thanks to all who offered advise to try and get it back up and running.