Thanks for the reply, I have already tried those links which do not take you to an address - the revenue website just sends you round in circles (it would obviously be too simple and efficient for the government to just print a return address on the form) in the end I had to call them so for anyone else reading this thread you can send any CGT return to:
Collector Generals Division
Sarsfield House
Francis Street, Limerick, V94 R972