If you are able to get a machine for less than £30K to work at 0,01mm please let me know. It really cannot be done at this level of investment. You can get close to 0.01mm but if you are lucky and the moons align you may hit it one day. I would be content with 0.05mm on any milling job even professionally done. Thermal expansions and other sources of error will conspire against you.

May I suggest you go to the various shops and have a look at the machines? They are all much of a muchness in terms of quality and build. Its the extras that really make it.