Hi Mark,
Welcome to cnczone. The Taig mills are nice but I see what you are saying about the price. Being an inverter, have you thought of building you own? There are many resources out there to help you out and there are a huge number of knowlegable people that run through this site that can give you some awesome pointers, especially some of the MOD's. We all love to see photo's of machines at embrio stage and love to see follow on photos to watch the development and growth stages and most of all that photo of the final birth when the breath of life is given via cnc axis motion. Oh!!! I think I'm gunna cry.
If you want any info at all just pm me and I will help you out as much as I can, otherwise take a look at the threads on this site all about this subject. As far as second hand in the UK is concerned, I dunno as I live in the land of OZ.
Take care Champ!!!