Having thought about this for a few mins, I am now a little unsure that a 200W servo will be powerful enough for my table. The Omron R88M 200w motors produce 0.637 Nm continuous torque with a peak of 2.2 Nm.

I think I noted in one of my first posts on this forum about stepper replacement that Fehlmann now fit Omron 400W servos to the P21 which is a similar machine to mine (but with a slightly larger table) - I'd forgotten about this until doing some searches earlier on.

I suppose that if I do as you suggest Boyan and fit the servos with a 2:1 reduction a 200W Omron servo might be adequate. Being more optimistic, a reduction of 3:1 would produce the best part of 2Nm continuous torque - which will probably do the job.