20 MPH limits have sprung up all around here as well, and yes people will sit right your arse, or go flying past gesticulating / mouthing etc.

Fu*k em it's their licence.

I don't get out to remonstrate with anyone any more, as you say likely to get stuck with a knife.

All the fun / enjoyment is being squeezed out of driving little by little, whether by speed limits or mindless morons.

Not long back from ride on the H2, not a bad run although came up behind a line of slow moving traffic on the last stretch towards home, caused by a bloke in a van deciding that the national speed limit is in fact 40, in fact every speed limit is 40 FFS.