i have a used SAS wheel clamp. ideal for caravan/trailer or indeed car.
gets really good reviews, caravan insurance approved. complete in carry case with 2 keys
http://www.sasproducts.com/acatalog/...SAS_Clamp.html
retails for around the £70 mark, looking for offers around £40
can get it to any national or west mids regional as heavy to post, pics available just pm me an e-mail address
tks