Nige,
I was in a similar position and in the end I went for an old Colchester Student with a gap bed.
I managed to find one with very little backlash and it's superb.
I converted mine to single phase without much faff but you will be limited to about 4HP if you are wanting to run it from a socket, mine is ok like this, only thing it wont do is set off at max rpm with a cold gearbox (it trips the breaker), once it's been used for 5 minutes it's fine though.
I know where there may be one for sale but it's in Derbyshire...
HTH
Mick.