Due to the COVID-19 pandemic, DVLA relaxed the requirements for HGV drivers who are renewing their licence, to require a medical examination. (FULL DETAILS HERE).
Any driver who gained their car licence before 1st January 1997 also gained a Cat. C1 licence enabling them to drive a vehicle up to 7500kgs. However the DVLA have announced that the temporary exemption DOES NOT extend to those with the grandfather rights.
The DVLAs decision means that any such drivers will probably be unable to renew their licences until D4 medical examinations are restored after lockdown eases.