Grinding starter motor

Hey all,

For years our Mk2f has grinded a bit when starting, especially when it was starting from warm - it usually sounded like a bit of a grinding slip just at the end of the starting stroke, presumably when the flywheel was being spun by the started engine and it slipped on the starter motor gear.

The grinding is ever-present now, which I assume means if it is indeed due to gear / flywheel teeth wear that its only going to accelerate to the point of no-return. Is there a simple way to check the teeth etc? There's an inspection plate on the gearbox that I've never had off, wondering if its for that reason.

Pulling and replacing the starter looks straightforward enough, however it looks like it might be more on the gear / freewheel end of the starter assembly. There's even some 'repair kit' parts listed like number 15 here:

https://volkswagen.7zap.com/en/rdw/polo+derby+vento-ind/po/1993-120/9/911-96000/

Perhaps the engaging lever hasn't been fully disconnecting the freewheel gear?