you will need a selection of torx bits for this


start by folding the rear seats down then remove the covers from the rear seat back mounts

https://www.fiatforum.com/attachment.php?attachmentid=208479&stc=1&d=1587991622

next remove the two lug holding to boot carpet in place they should screw out

https://www.fiatforum.com/attachment.php?attachmentid=208480&stc=1&d=1587991622

then you can remove the two bolts holding the rear seat bases in place

after removing the screws lift the front of the base up then pull it forward out the way and rest against the front seats


pull the door seal out the way then you can get your hand behind the trim and see the push pin type fixings if you have trim removal tools you can try and get them behind to aid removal by popping the fixings out the bodywork

just work gentally one at a time and you should be able to pull the pannel away and forward enough to get the upper gray pannal away
https://www.fiatforum.com/attachment.php?attachmentid=208482&stc=1&d=1587992063

next to remove the gray pannel you will need to poput the cover for the fixing bolt under the (airbag) word dont worry there no actualy airbag here
after the bolts is removed it just plastic fixing against that come away with a tug
https://www.fiatforum.com/attachment.php?attachmentid=208483&stc=1&d=1587992448




finally to get to the pannel holding the boot light and power socket theres 4 two part fixings

to remove these pull the centre out then get nehind and pull the whole fixing out of the part

https://www.fiatforum.com/attachment.php?attachmentid=208484&stc=1&d=1587992625


after the 4 fixings are remove its just trim clips again that need a pull to remove




and viola your done and have access to the rear seat belt mechanism and wiring leading to the boot hatch also if like me the rear washer tube that i had to repair

https://www.fiatforum.com/attachment.php?attachmentid=208485&stc=1&d=1587992769