depends if the escort van is a 35, 55 or 75, an empty 75 would be ok, a 55 is the most comon and i think would be on the limit if not over, a 35 no chance. the van will have a plate somewhere telling you the axle weights, and train weight, a fiesta is light at about 750kg when i weigh them in, that on a light weight brian james trailer of about 400kg gives you about 1150kg at the minimum, now as long as the gross train weight ( van and trailer) and the axle weights of the van and trailer are under their max, its ok to tow, but having said all that as you passed test after 97, you need to take a test to tow a trailer of that size and weight.

don't listen to any of the sheep that follow each other and say you can only tow 85% of the tow vehicle cos thats complete bollox, most big 4x4's can tow well over 3 tonne and they only weigh in at about 2 tonne or 2.5 tonne, and a mondeo weighs about 1300kg but can tow 1800kg, with a comercial vehicle from a fiesta (without windows) to a truck, it all comes down to axle weights and gross train weight (GTW), cars get given a max tow weight normally because they are driven by sheep that need to be told everything!!!

the max pin weight should be about 75kg no mater the weight of the trailer if it is loaded correctly, even if the trailer is 3.5 tonnes, it should be loaded/ballenced to give the pin the correct 75kg, if the escort van is a 75 you have 750 kg to play with in your gross train weight as its a van, if the van is emty you can tow 750kg more than if your van had 750kgs of spares and tools, although the 750kg does include the driver and passenger,

but as i said before, none of this is relivent till you pass you towing licence, but i thought it would be usefull info for others, and this info is verified by a friend of mine at VOSA, and VOSA is who will do you more than the police, although the traffic police are almost as dangerous to get pulled by with a van and trailer or anything your not sure about