How about this.........c-----r is the in credit bit.........u is the unionist...........and rat is the traitor.......O is the nothing........ bit strained isn't it????
Thanks Slaney - just woke up, having dozed off in the chair! I realised you meant 22d after I'd sent the message and then completed the crossword with "epsom".
Looking forward to tomorrow's cryptic - Friday is usually harder!