Many thanks mate. Thing is, if you press and hold the lock button for 2-3s, you also disable the volumetric sensors as a by-product.
As for reverse dipping mirrors, do I set it to L, shove it in reverse, the adjust the mirror down and leave it and when I drive it away it will reset to 'as-before' - does it also mean that if I leave it on L and select reverse, it will remember the dipped position?