Rear boot access!....

If you think you can gain sufficient access to inspect what is needed in boot then test it , if not able to see properly, refuse to test

This could go either way. Technically it should be a refusal to test according to the manual.

BUT you say the glass opens. By this I presume you mean the rear screen ?

Are there any components requiring examination which you would be prevented from fully examining without the boot open.

I'm thinking of items such as the rear upper seat belt anchorages for instance. If they are within 30 cm of the tailgate you will need to check inside the boot/tailgate aperture for corrosion.

Yes the rear screen opens which allows access to the boot area and also the latch to unlock the boot door. However you cannot use the handle switch to open the whole boot door that's faulty.
So you can test items in the boot area all be it restricted. Its a advise me thinks....would it be right!

A few minutes on Google brought up some photos of the boot layout of a Stilo estate. Looks like access through the window, or by folding down the rear seats should give sufficient access.

Proceed with caution jl and issue an advisory as to how you accessed the boot/load compartment.

Do tell us why you think the catch is a prescribed area ?