Are you double clutching? S2A has no synchro between 1st and 2nd. Proper procedure to shift up from 1st is to press clutch in, shift to neutral, release clutch, press clutch, shift into second, and release clutch.
Shifting down from 2nd to 1st while moving is a fine art and requires this same method with a throttle blip in the middle. Generally, I advise against it.
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.