TrigpointingUK

A 1638 Manorial map from 1638 shows a windmill in the vicinity of the present Warden Park School at Cuckfield.
Its omittance from the 1808 map suggests it had long gone by then. The field in which the mill stood was still named “Windmill Field” in the 1843 tithe apportionment. Interestingly the 1910 OS map shows a trig point alongside ‘Park Barn’. Trig Points tend to be placed at the highest spot. I’ve found a lot of instances where trig points were placed at mill sites. I wonder if this were the case here?

It's very possible, but unfortunately we have no comprehensive list of 19th century triangulation stations against which to compare, and few have been found in the field.