Stone Flags - Pros and Cons

[Lime]

The main deterrent was that I don't like the idea of a pneumatic drill and all the vibrations on a very old house.

Neither would I.
I'd use a large angle grinder and slice the floor up into ribbons.
A hammered wedge in the slits would soon break the concrete.
If the concrete is deeper than the cut of the angle grinder then a second or third set of cuts would be needed.
It will be a very dusty job but with little vibration.
If your builder can't see the sense in reducing the vibration I'd change my builder.