Why is that then
I know what I see on a daily basis
For a start, EU law dictates that HGV speed limiters are set at 56mph/90kph, in England the NSL for trucks is as follows:
Single carriageway: 50mph
Dual-Carriageway: 60mph
Motorway: 60mph
UK law is that a HGV can travel at up to 60mph legally, hence why we'll often let the trucks use weight and gravity to overrun on downhills as it means we can overtake quickly and make up ground. While I'll happily admit there are plenty of bent firms out there running with overrides for the speed limiters, these are few and far between and definitely not so stupid as to cruise along at 70mph in the outside lane.
Also you don't see trucks in the outside lane on a daily basis, I drive up and down motorways as a HGV driver and haven't seen anyone ILLEGALY in the outside lane in over a year.
And there’s no way that speed limit can be changed? I’ve been tailgating doing 50ish countless times and overtaken by them and it sure seems too quick for 56mph. Same with loads of company and parcel delivery transit vans that sometimes have stickers on the back saying limited to 60 or 70mph when all I ever see is them in the outside lane keeping up with everyone who are easily doing 80+
It's not just a switch you know, the speed limiters are wired in with the tachograph systems and are complicated to override, if it was that easy we'd all be doing it. And trust me your local DPD/FedEx isn't running dodgy limiters.