NT formulated the question :
but they're rather ineffective now. Go back to the 50s and you can
drive with them.

Both of mine are modern and if I wanted to, I could lock wheels on both
with not very much effort.

I appreciate that they have now reclassified them, but that is not
reason why they should be any less effective.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk