To be honest Jo' it was me that decided it was alcohol based! I have had a bad past history and now find that the hand is no longer soar if I limit my alcohol intake... however if I go on a mad multi-day session it flares up nastily.
I will have a look into an MRI scan, I had one a couple of years ago when I was admitted for a post alcohol seizure, but I never got any feedback on what they were looking for (other than 'we cant find anything wrong with you') - I did have entrapment surgery at the elbow, but again they said the nerve wasn't trapped, just tight. They apparently 'slackened it off' (???), but there has been no improvement and that has almost been 2 years now.
Thanks for your input Jo, it is much appreciated.