Martin4,
to get a class one with deviation you just need to book a medical and turn up at the CAA, in the same way as anyone else would. They will examine you, inc ur eyes, and decide whether they will pass you as you are, pass you with deviation or not pass you at all. The awarding of a class1 through deviation is their decision and is instigated by them, all you need to do is turn up and see what happens.