I'm sure Lee will reply Ed but I can say why from my perspective.
To park you need twice the length of a van/car.
Everything is out in the open and people can tamper with it.
VOSA will pull you if you are towing a trailer, even if it is all in good order.
Unless you have storage it is going to be in the elements all year.
The only trailer I would have (I have had one) is an Ifor Williams 105 or 126 because they are as good as a van but again if you get into commercial and start travelling you should legally stay within 50kms of your operational base or you will need to have a tacho fitted to the towing vehicle.
Rob