Hi
I have a 2013 Fiat 500L and the boot release catch is hanging diwn

Can anyone help on the steps to remove the plastic shell and reattach the boot release catch from the inside?

I can see some black screws but they don’t seem to come out completely and if levered out/down a cm or two nothing moves.

I have an MPW (long) version but it shouldn't be much different.

How to open the boot from inside is in the manual. Just use screwdriver in proper place
Than take off plastic shell . There is one screw/bolt only around the inside handle . Under little plastic cover.
All rest is holding on plastic 'fir tree' fixing clips. I used just hands to pull it off.
The latch itself has 2 screws visible when you open the boot lid. Disconnect the wire connector. Check for corrosion/water damage inside the connector and socket. Problem could be only there.
The latch looks like not repairable part. But if you open it in some way check motor connections as it is likely to corrode as well.