Thanks for the replies,
As it's only 1 cm at the moment the CAA have issued an OML which doesn't really effect me as i only fly the G5. I do however need to look at treatments and the outlook maybe brighter than i thought. The doc at the CAA was so very nice and helpful, it was great to talk to him. I am lead to believe other class one holders have had the Gama Knife radiosurgery and returned to flying after a couple of months so that's good news as well. Not too keen having someone cutting my head open, need to keep hold of all the sawdust i can!!
Thanks again guys