I would say that if you can get 1Kw for not much more then it would be better.
Just looked at the specs of the drives/motors and the one you linked to earlier is actually 5000rpm max but only rated 3000 rpm so you probably wouldn't be able to gear it too much in comparison to the original.
It would depend however what the original was actually supplied, voltage wise, from the Norwin drives, it may have just been 90v which would mean approx 2000rpm would have been the normal max rpm of the motor on the lathe.
As said I just looked at the specs and that drive can handle 1KW motors so it would be fine, they show three that are compatible. Just different inertias, I would probably opt for the medium inertia myself.