...I come here as usual after my web search leaves me with nothing
conclusive..

I don't know if it's because the weather here had, until the last few
days, been exceptionally mild but my heathers are coming into bloom
and yet I pruned these in late May this year after a spring flowering.

I gather some heathers will bloom twice and after an autumn flowering
will bloom until the first hard frosts. Would they benefit from a
winter pruning too?

I've got a daft clematis that's coming into leaf about 5 months too early. But normally a mild autumn promotes some flowering of my rhodies - I had one in full flower this time last year, and that hasn't happened this year. October was very pleasant, but the last couple of weeks seem to be very normal for the time of year.