Encouraged by the above posts I pressed on with my online application.
Although my current licence expires this August, it told me my Photocard is valid until July 2021, presumably that is 10 years since I last provided them with a photograph. It gave me the opportunity to renew the photograph from my passport, so I gave them the number and they said my 18 month old passport wasn't valid ?? I will have to wait and see what happens when they consider my application.
I can't be the only one who refers to the piece of plastic as a driving licence, particularly as it says DRIVING LICENCE at the top, however it seems that is a Photocard, which made sense when there was a separate paper licence.