pacsafe & alarmed padlock
yes, Pac-Safe is the brand, also try to search eBay.co.uk for "pacsafe" or "pac safe" they are cheaper than on the official site.
When I go camping I use a strong chain and an alarmed padlock (Oxford Boss), it is not as loud as a car alarm but if you are sleeping in a tent or near your bike it will wake you up if somebody is trying to fiddle with it or move the bike, it can also be used as a disk lock. Again you'll find on eBay for about £50.
... and Nelly The Elephant packed the trunk and said goodbye to the circus...