As far as i know if you have insurance they have to cover you for diabetes if you get it after starting the policy so you will be fine i think.
I think you should tell them otherwise it might make your policy void if you did need to claim for anything even non diabetic related.
You can always...
I am in the process of buying my first home and am so upset and angry that i cannot find a company who will offer me critical illness cover and Payment protection cover does not exclude my diabetes and any future diabetes related illnesses i get. How are diabetics ment to get cover?? I would...