James wrote:

But I wasn't peeed off with the advice, which was sound, just the
tone you always get around here of hypocritical finger wagging every
time someone brings up a small misdemeanour.

That's the fun of Usenet ;-).In many cases, it's not hypocritical.

I was tired, it was midnight

finger wagging
So? If you're too tired to drive properly you should stop and take a rest.
Tiredness causes more collisions than drink driving.
/finger wagging

and I crossed a deserted Tower Bridge at the outrageous and
indeed _criminal_ excess speed of 12mph.

AIUI the limit is there to keep damage to the bridge to a minimum. There was
a suggestion at one time that it should be closed completely (except
possibly for buses and emergency vehicles) to vehicular traffic.

Get out the birch twigs.

They're too good for the likes of you!! :-)