Lord muc your good at 78mph on them its likely other people getting flashed not you, I’m in the horsham area in Sussex so up and down the m23 alot. in my 8 years driving 20k a year I’ve learnt how far you can push and 78mph seems to be the sweet spot, haven’t had any points and I’ve seen people going a bit faster than me and get flashed so tried and tested. Have to add its on 18″ wheels as larger wheels will likely be slightly faster. Also most cars are actually 3mph out on the speedo also tested by one of them speed reader signs, ifs always 3mph lower than what the speedo says.