... on a patchwork off different frequencies across the UK due to the poor propagation of VHF

Doesn’t RDS mostly solve that for the most common case where frequency changes becomes an issue (car radios).

Yup, and DAB also still works.

Umm mostly. IMHO DAB is a failure, at least for vehicles.

I listen almost exclusively on dab in the car. It auto fails to FM but it’s rare I go somewhere where that happens.

It’s probably highly variable depending on location and the quality of your radio/antenna. It’s useless where I am.