Further to my earlier post - I went back to the CAA and made it clear that my restriction was medical. I recieved the following response:-
.....In future all medical restrictions will be shown on the Medical Certificate only, not on the licence.
EASA will not issue licences. EASA Part-FCL licences will continue to be issued by the National Aviation Authorities - in your case the CAA.
Any medical limitations will be those shown on your medical certificate, which will apply to all licences you may hold.
So it looks like I can get an EASA CPL if I jump through all the hoops, although the hoops remain illogical and unfair.