LMSC
So I gave the grinder a good clean yesterday - removed all grinds from screwheads with a toothpick etc. - it looked as clean as the day I received it. First coffee this morning I put 18g in and got 17g out so 1g down from the first grind after cleaning. Will measure the other 2 grinds I do today and edit this message as I go along.
Grind 1 - 18g in & 17g out (1 gram loss)
Grind 2 - 18.5g in & 18g out (0.5g loss) - planned that one perfectly haha
Grind 3 - 18.2g in & 18.1g out (0.1g loss).
Quite happy with that as it goes.