When my old Provost (WW388) passed to the South Wales Museum back in the 80’s for preservation, they had a full set of windscreen transparencies.
This included a sliding canopy, side and lower cowlings and most of one Alvis Leonides Engine spare as part of the package.
Unfortunately, despite some excellent leads through this forum – I couldn’t connect to the current owner of the Provost when I tried some months ago.
I wish you all the best – in case you have better fortune down that route. The spares came from XF898.

Very best.