Anemometer Now Working
Further to my earlier entry, the impeller in the anemometer has started working again. Some time after 13:00 this afternoon wind speeds were being recorded again. It would appear that today's rain and wind has finally cured the problem.
I'm still not sure if this was another case of heat causing a problem (initially this seemed possible given that when it first stuck we were having some very warm days, but the last couple of days have been much cooler) or if something had got stuck and the wind and rain has finally cleared it (I have noticed some webs around the anemometer so it's possible that a spider is to blame this time). It remains to be seen if the problem will return when winds are lower than they are now.
Either way I guess that, at some point soon, I probably need to get the anemometer down and give it a good clean (not such an easy job given where it's located).