Read
321A(1).
Without expanding too much, your argument about a Tier 1 visa holder being able to visit is the same as saying someone with a visitors visa, because they are allowed to be here, might as well allow them to work as well. There is separate visa categories for visitors, students and people wanting to live & work here. If a visitor and some categories of students cannot work here, why should the reverse be allowed.
You will have a super-hard time convincing anyone that you intended on seeing any recruitment agencies between 24 December and 1 January. (And look for accommodation in this time too!).
I'm not saying this will be impossible, but please make sure your story is credible. Saying you had recruitment agencies to speak to in this time is simply not credible - unless you genuinely had some appointments booked?!?!?!