We've made multiple attempts to speak to the DVLA. However, they've yet to respond. But this is written under the over-70s renewal section on the DVLA site:

You can drive while your licence is being renewed if you meet all the following conditions:

- you have the support of your doctor to continue driving
- you had a valid licence
- you only drive under the conditions of the previous licence
- your application is less than a year old
- your last licence wasn’t revoked or refused for medical reasons
- you’re not currently disqualified
- you weren’t disqualified as a high risk offender on or after 1 June 2013