Blame the Post Office, unless the address was wrong or unclear, unless...the date of the letter was 26 days ago, and the postmark was later or not there, which may indicate that there was a significant delay at the DVLA due to 'understaffing because of COVID restrictions'.

I'm sure that'll be the go-to excuse for all and sundry for the next year. Good organisations and firms sorted things out in a matter of days/weeks, many others have done anything meaningful in 6 months, or are just starting to because of public pressure after their failures were publicised.

I recently bought a second-hand car - the new logbook arrived within 9 days

It's been well trailed that while anything that is electronic is being done in normal timescales. On the other hand physical paper handling or anything involving human intervention/discretion is taking a lot longer due to problems making the Swansea building a COVID safe workplace.