Fairey Aviation at Hayes in the mid-1950's built Gannets for the Fleet Air Arm at their factory at Hayes. The unassembled Gannets were taken by road to RAF Northolt where they were assembled, and flight tested. Not sure where they went to after that.
I know this because in the summer of 1955 I was on temporary detachment to Northolt and wandering around the station getting my bearings was astonished to see a hangar full of Gannets in various stages of assembly being assembled by civilian workers. ISTR output was one Gannet a week, but am not 100% sure of how many.