"Robin Nicholson" wrote
But of course the long term averages are the key thing and here I am
stuck, as the nearest place to me with records is presumably
Yeovilton. And that is about 20 miles, north west side of the North
Dorset Downs. Do you have any long term averages?

I am about 1.5 miles SW of Bul Barrow (274metres), but I am not at
all sure whether that modest height accentuates rainfall. But of
course, snow falls there in winter quite readily.

Robin, if that puts you a few km SE of Shaftesbury, your 1941-70
mean annual rainfall is 960mm, approx 30% more than Yeovilton's.
If you have more recent averages for Yeovilton then simply apply
a 30% blanket correction which should get you close.

Always bear in mind that AWS rain-gauges typically collect up
to 10% less rain than a standard manual gauge. Sometimes the
difference is even greater. I'd always recommend having a
manual gauge alongside an AWS one.

Philip