...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?