Congratulations!
The white roads probably are cop/camera free; the gold B roads might not be, it depends on the traffic. Still, a regular-speed recce journey always helps, and some of the maps sold in the UK also show fixed speed camera placements.
Things are (probably) run as rigidly up north, however the density of cameras, at least, is likely to be a lot less, especially out in the countryside. To be honest, on some of those narrow twisty countryside minor routes, the national limit will seem perfectly fine.
Oh, and:
The Watford Gap on GMaps This is sometimes taken as the dividing line between North and South England
