Hi Gareth
I would say the Oil Pressure Switch would have to be on one side or other of the engine block,about half way up (usual position for most switches on the main oil gallery).
Don't know whether the car has electric power steering (EPAS), in which case it won't have a PAS reservoir fitted. Some EPAS columns/racks did have a small reservoir on the very bottom of the column (electro-hydraulic)
Let us know what you find
Cheers Trevor