If you are in England/Wales all prescription items (insulin, needles, testers) will be free. In Wales all prescription items are free to everyone. In England as a type 1 diabetic you get a medical exemption from the usual prescription charge - to get this you will need to fill in a form (
@Daibell ) and get your doctor to sign it, then you will be issues with a medical exemption card and you will be able to tick that box "has a valid medical exemption certificate" on the back of your prescription. Your GP receptionist should be able to help you with getting the form and completing it..
In England & Wales, type 1 diabetics don't have to pay for eye tests.
There's no diabetic exemption for dental charges. But there may be some assistance available, here is some info on when you might get help with dentist fees -
http://www.nhs.uk/chq/Pages/1786.aspx?CategoryID=74&SubCategoryID=742