its only like £6 ($9) more, which is about the price of a meal in McDonalds, which is why im not really fussed about spending that little bit extra for peace of mind.
however, i searched for the bulldog ones and found three that were cheaper than the kryptonite lock. i think ill have to read through the reviews before i decide on one. here are the ones i found in case you are even remotely interested :)