Speed limit for vans 50mph, lots of people tell you that it's nonsense but it's not.
The police will sit right behind you here in Glasgow and wait for you to move up every time they get closer then pull you for it, I always stayed at 50 and a bit below.
Also watch your driving licence if you get into one of those big tall Mercedes vans or a Ford transit tipper as they can be over the tonnage for a normal car licence even empty never mind a 1 ton pallet of cable.
My uncle has been driving for 40 years and he had to do an extra test and get a special licence to drive a big Mercedes van for his work, I see most people jumping in any size van and driving about with a full load, that's all well until you get a random traffic stop and they look at your driving licence then you can be classed as driving without a valid licence and get banned and heavily fined immediately. ( think a ban between 2 and 5 years points on when you go to apply and sit a driving test years down the line for a new licence and a fine of up to £1,000)
Google weight limits for a standard UK licence.