I'm answering my own questions here!! But for completeness I'll post em here for future searches. If you have a valid Tower and Approach rating, you are exempt from the Theory Examination for RT/Comms.
You still require a Practical - though it should be straight forward at best!
Here's a list of examiners:
http://www.caa.co.uk/docs/33/2012082...gust2012v7.pdf
And I'm spent. Time for some vino.