Basin, as far as I understand it, if you have a JAR-PPL, then you have to comply with JAR as well as UK rules.
If you have a medical issue it's better to 'phone the CAA MEs and ask. I did that last year as I was due to get a surgical operation. I was told you must report if you receive an appointment to have an operation - even if the appointment is some time in the future. The CAA MEs are very friendly and happy to answer any queries. I've had to contact them more than once and have nothing but praise for the way they handled my queries.
