I have been trying to renew my PCV and LGV licence since May. As I’m over 70 I have to renew every year. I have to have a medical and complete the D4 form. Last year the DVLA waived the medical because of Covid and renewed my licence without a D4. This year I asked the question “Do I need a D4” they emailed back saying no. I submitted the renewal form and my licence only for it to be returned weeks later requesting a D4. I had a medical and submitted the renewal again with the completed D4 on 2nd August. Still waiting for it to come back!! If the DVLA have received a VALID application you can still continue to drive on an expired licence until the application is approved or refused in which case you will be informed in writing. That would only apply in this country not abroad.