Hi Thanks for responding,I think you will find that all these figures, including those from Bath, assume a typical caravan matched with an appropriately sized car.
My setup is a bit non - standard, and I have never had any trouble with it, even in quite blustery winds on the Severn Bridge.
The van is a Sprite Compact pop-top, with a weight of 685kg, and all storage is at waist level or lower.
The tow car is a 1989 Range Rover, and all heavy gear (eg awning) is packed in the car with the rear seats folded, so that most weight is kept forward of the rear wheels.
The caravan, top lowered, is barely higher than the car, and the ratio is probably about 25%
A daft anomoly in the rules is that my wife, on her post '97 licence, can drive this rig, but if we got a bigger van, she would either have to take an E test, or, and this is the daft bit, WE WOULD HAVE TO GET A SMALLER CAR!
I'm glad that teh weights are as low as that - so happy caravaning.