The expiry date of your photo is shown in section 4b on the front of your driving licence. If you don't have the D46 form, you can pick one up from a Post Office or you can use the D1 application for a driving licence form.
DVLA will automaticaly send you this form 90 days before your 70th birthday. Go to this website to start your application. If you dont have one or need to re-register, youll get an ID as part of your application.
You can renew your driving licence online for free if youre 70 or over or soon will be by using your Government Gateway ID.
