My AA driver would have followed the Tomtom around an illegal right turn
if
I hadn't told him not to. I wonder if people using them get fined more
often
than people using maps?

Well, that is the drivers fault, rather than the Satnav. Following Satnav
shouldn't affect your reading of road signs and road layouts. I have only
had such a thing happen once, and afterwards I set that as an avoidance area
and it has never happened again.

Most good Satnavs, once you drive past the prohibited turning, will work out
another route anyway.

Best Wishes,
LEWIS