Being over 70 I have to renew my license every 3 years and can say without doubt that the DVLA web portal is the worst I’ve ever used.
Used it last year and had to input my details 3 or 4 times before they got excepted with times out and so say incorrect input on top of there second rate computer servers. The first few tries were during busy times of the day (mid morning) so I tried and was successful mid afternoon.