Sacha wrote:

Last night was pretty windy - second or third night in a row - I'm losing
track now and now the wind is building up again, after a fairly calm day.
This seems to be the pattern over the last few days. That surely cannot be
explained by katabatic winds at this time of year, surely?!

Hmm. Katabatic winds can occur - particularly where you have sudden
cooling at the top of hills etc. following a relatively mild day. Your
proximity to the moors may the reason for this since cooled air at high
altitude travels downwards as it increases in density.