Well as a lorry driver I am willing to take the blame for all of it
but seriously, with regard to the OP the trucks shouldn't be overtaking there, and risk more than any car driver if caught, that said I don't like the idea of restricting overtaking unless it is for safety reasons.
As someone states later through this thread, we do it differently to Germany where there are miles of motorway with one lane for trucks all having to go as slow as the slowest truck, I have a high horse power truck that goes up hill as fast as down hill and very often find myself having to slow down to as little as 15 or 20 kph behind some old truck with an empty outside lane on the motorway but have to sit there, if you think 2 miles of A14 is frustrating try that for 70 or more km on a German Autobahn. and then there is the one lane left for the cars as they don't like coming into the lane full of trucks. When I have the misfortune to drive my truck in Germany I average 100 km less per day compared to the rest of Europe, and my fuel consumption goes up by around 4 ltr per 100 km,(10% more) I usually feel more stressed at the end of the day as well, still it is good for the car drivers as they get to sit in car queues without us getting in their way
With regard to overtaking in the UK,(or anywhere else) when I am approaching a slower truck I will overtake it if I am faster than them, because the sooner I finish my driving the sooner I get to take a break, 13 or even 15 hour days are the norm in trucking so I want to finish as soon as I can.
When a slow lorry is passing me, as long as I am not on a hill I will ease off the gas for them to pass me, I do this for two reasons, I like to keep as much free space around me as I can in case something happens, and I don't like the idea of big queues forming behind me as when I want to overtake it is harder to pull out.
In fairness to the car drivers in the UK, I think they are the most truck friendly in Europe, I hope it's not because they feel intimidated by us.
I drive an average of 110,000miles every year, and I don't want to spend any more time than is absolutely necessary stuck behind a slightly slower truck.
Maybe the way forward is to campaign to ban speed limiters