Just been outside taking my LH switch apart as for some random reason the 'pass' switch was sticking. Stripped it, a fiddle here and a blob of grease there and bob's your badger it no longer sticks.

However, am probably paranoid but the switch works literally only when it's fully pressed in (if that makes sense). Is that normal? It does work but feels like at the last mm...

have you taken the whole switch apart? it could just be a ruff edge on the push button or the spring has come loose and got traped.
the little contacts may also have been pushed back which would explain the full pushed in problem.
bring the bike over tommorrow if you need a hand.