the only parts would be the clutch plate or brake pads.

And it would be extremely unlikely at that age/miles those parts are original. Of course actually proving that will be harder.

If it is really such a sticking point, only option is to replace. Although if you were looking to modify the car at all in the future, then now might work out ok to put a better clutch in the car. And besides, at 120k, might do no harm for a new clutch anyway.

Brake pads hardly a big deal as they'd be easy and cheap

Given the overall purchase cost of them these days then shipping, I'm sure a new clutch really isn't much