A big thanks goes out to Jazz_North and Stephen_Fairhurst for their prompt and very useful replies.

I'm pleased to say that Winamp is now my default player from within OrangeCD.

For anyone with the same request here's the Command Line Additions

"C:\Program Files\Winamp\winamp.exe" "%1"
"C:\Program Files\Winamp\winamp.exe" /ADD "%1"

Happy days