Thanks for the info Rory and there's absolutely no need to apologise for being straightforward - it's the only way to be in my book. My comment about scanner resolution was an attempt at humour from an aviation perspective; there's no doubt that if something's wrong it's better found earlier.
Well, the "small area half the size of a peanut in the sensory bulb" now has a name, it's a "right internal capsular small stroke due to a blood clot". Methinks bugger would be an appropriate adjective at this point!
I grounded myself when it happened but will have to tell the CAA now that the problem has a name - is it feasible to regain a class 1 after an event like this if there are no other changes? or is it gone "at a stroke" (I promise not to retrain as a stand-up comedian).
B Rick