I'd choose UCL over the three, for several reasons, but first to address Justice's points. The reason we only have one essay per term this year is because of our mid-sessionals, otherwise we would have another assigned essay (as is the case with Property I). Having weekly tutorials could be beneficial in one sense, but I think it would lead to too much spoon feeding- it can sometimes be bad enough now (When people haven't done any work). It could be worth pointing out that there are at least 3 people studying Law at UCL who started at Durham and disliked it so much they dropped out and reapplied.
Having been at UCL for almost a term now, I would recommend you visit all three universities and consider your options carefully. In terms of careers, none of these unis will disadvantage your prospects unless you pick a uni which is not the best for you. UCL and KCL are never going to provide you with the atmosphere of Durham. But then, nor is Durham going to provide you with the array of opportunities London presents. But you could be satisfied with the nightlife in Newcastle. The general perception amongst Durham students does seem to be that it is a university in decline.