Dual Mass Flywheel....

In most UK vehicles these seam to be good for 70,000 miles or so.... treated gently....

Personally for the extra couple of hundred £££ I'd change the lot if the vehicle is in bits...
ie flywheel, plate, clutch disk and release bearing as a job lot.......

If the flywheel develops too much slop it will give a clunk on engaging load and shock the gearbox.
If the fly wheel develops lateral slop it can run off centre and load the crankshaft rear bearing and crank shaft itself significantly....
this will cause you a vibration when rev up-down and serious engine damage is a risk, let alone gearbox input shaft and primary bearings......

Generally, as you say, a cm of rotational freeplay is acceptable, and they arrive NEW with this.
If you have 50k + miles on the clock and are spliting the engine/box, Personally, cash permitting, I'd change the lot for peace of mind.

Have a great day.

Grant