Aubrey,
What a motor you have! I have the same model and take it from me they will pull any van on the market but what specifically do you want to know? ie. kerbweight, towball weight, engine power or what?
I recommend you join ITOCUK , the online owners club and if you havn't already done so order a UK translated hand book from the club - this has all the facts you will need - they also have an active forum including a towing section.
Your van is probably circa 1600 kg MTPLM which a Bighorn will pull with ease with it's KW of about 2.2 tonnes and a max tow of 3.2 tonnes. Cant rember the exact towball limit without looking it up but it's about 130 kg.
Hope this helps - if you need more info, give me time to look it up in the book first but rest assured you have one of the all time great towcars.