One in three nights, excluding the summer, is pretty good. Who was it who said “You’ll not see anything from there” when you moved up to NE Scotland?
I’ve had a look at my observing stats from Chelmsford but they are rather meaningless since I’m often not able to observe even if the weather is clear. Anyway, I obtained CCD images from Chelmsford on 107 nights in 2014 so rather worse than your one in three. I suspect it would be better if I was a gentleman of leisure…