Not sure you can buy that piece separately, but here's the switch minus the knob: https://www.roversnorth.com/parts/pl...ries_early_iia
The dash changed over in 1967 when they went to negative earth and a single dash mounted wiper motor. Yours is correct.
61 II 109" Pickup (Restomod, 350 small block, TR4050)
66 IIA 88" Station Wagon (sold)
66 IIA 109" Pickup (Restomod, 5MGE, R380)
67 IIA 109" NADA Wagon (sold)
88, 2.5TD 110 RHD non-hicap pickup
-I used to know everything there was to know about Land Rovers; then I joined the RN Bulletin Board.