AmigoMV6 .... and breathe .........

The rules have been around for ages and make a huge amount of sense.
Your artic prime mover was designed .. power, brakes, chassis .. to be able to pull a full trailer up to its designed (permitted) weight .. thats what it was built to do.
A car was not built to tow a trailer specifically .. but has a certain ability to do so. The manufacturers therefore LIMIT the maximum allowable weight that can be towed, hopefully knowing the chassis, brakes, steering etc etc effects and limits.
That figure is published on the VIN plate and cannot, legally, be exceeded.
Some cars do NOT have a towing weight specified, and do not have the facility to fit a tow bar .... it is actualy illegal to modify and tow with such a car ... why ?? because the maker does not think it safe !!!
It matters not your level of towing experience or ability ... the laws of physics cannot be overcome by wishful thinking .. if the trailer ('van) weighs more than the car then in an emergency it WILL take control .. and you the driver will lose control .....
This happens to artics as well .. and they were designed to tow .. we've all seen the result of a jack-knived artic .. not a pretty sight ... it just gets worse with an overweight 'van to car setup.