Thanks for your help. That's reassuring as I'd begun to think it couldn't be MP because of the location - and as a worst-case-scenario kind of guy I didn't fancy many of the alternative causes (though I'm still staying in regular contact with GP just in case of course).

As for Lidoderms, they are (AFAICT) only prescribed in the UK for shingles / PHN, and even then only from specialists rather than GPs. But I'll fight that battle if it comes to it, and hope for a swifter resolution to this pain...

thanks again - Merry Christmas :-)