creaking noise passenger rear

Hi when I'm driving I hear creaking from the back on passenger side pretty loud

Garage tried look said suspension looks fine they think its the disc so they grinded it down abit but its still there now just getting worse

I've got video off the noise please ignore the tapping noise just the car seat rattle

Here is link to video

https://youtu.be/_D4J8Rma9xc

Renault Megan's 1.9 privilege 2005

creaking noise passenger rear