I cant help with info on UK purchases, all though there does appear to be quit a few which have been buying these mills in the UK so there should be some first hand advice posted later on.
But, do be awear. Going cheapest may & may not be worth doing. There are many different castings, and even quality of fitting these casting, plus quality of parts used on these castings that you may not get a mill compairable to something someone else has bought from a different dealer even though the description may imply so. Most times it is the little things that will add up to a mill being any good or not.
SO do take your time with your research and be sure of what your buying. And also understand it will take you more money than the machine will cost to reach a point of productivity. Tooling, working, measuring quipment, metal & other stock, software and many other things will cost more than the machine (maybe even more than a complete CNC ready machine). Ofcourse much depends on what your really wanting to do with the machine & only needing one or a few different type jobs to be done will cost less. But when it comes to CNC we all quickly find that there is so much that can be done that we expand out from our original intent.
Jess
GOD Bless, and prayers for all.