The time has come to buy a small mill suitable for watchmaking. Concentricity and accuracy of placement are the crucial factors, I expect and CNC may not yet be necessary. Has anybody experience of a machine known here as a Chester Champion BV20 which seems to be the same as the German Optimum machine (And is almost certainly Chinese...). Would this be suitable?

Tom,

Take a look at a American made Taig.

http://www.taigtools.com/mmill.html

Welcome to the Zone!

2200 rpm is to slow for your application.

These people make machines specifically for horological work. Not cheap though, but then again not made in China.

http://www.cowells.com/

Do you have a watchmakers lathe.

Phil:)

The time has come to buy a small mill suitable for watchmaking. Concentricity and accuracy of placement are the crucial factors, I expect and CNC may not yet be necessary. Has anybody experience of a machine known here as a Chester Champion BV20 which seems to be the same as the German Optimum machine (And is almost certainly Chinese...). Would this be suitable?

I've never seen a Chinese benchtop mill I would even regard as close to the necessary quality and function of a Taig for fine detail work like watchmaking, and even the Taig is definitely NOT something I'd want to do horological work with unless I had no other choice.
I would suggest either (1) dedicated watchmakers equipment, (2) possibly looking into higher-end Minitech, Model Master, or Roland mills, likely in that order, or (3) assembling something yourself from semiconductor and optical industry surplus (not as hard as you'd think, for your needs its actually quite simple).

The cowells machines look pretty sharp- :)