So I have a relatively positive update. Subaru Australia are supplying a new clutch as a gesture of goodwill, and the dealership has agreed to significantly reduce the labour costs as they were not upfront about the potential for costs when I took it in, and fit the short shift kit including all bushings for a very small additional cost.

I've accepted this on the basis that getting an independent mechanical report would cost more than my contribution, and I would have to shell out $1300 for a replacement clutch anyway with no guarantee of getting that back.

So thanks to Subaru for at least meeting me part way!