I looked up Gray's Hall in "The Place-Names of Fife", Volume Two, Central Fife between the Rivers Leven and Eden, under the parish of Ceres -
"GARR HILLS
The Ordnance Survey Name Book describes these as 'small heights on the farm of Hill Teasses', adding 'why they obtained their name is not known in the neighbourhood'. Roy (1753) shows Grayshall in the vicinity, which may be a garbled rendering of the name."
Harry