Octy Estate - how do I get to rear speakers?

My left rear speaker has stopped working - I reckon I've disturbed the cable when running other cables near it.

I've done a search and read several posts about this but I still can't work out how to get to the rear speakers!

Apparently the boot side trim needs to come off, but which bits need to be removed, and in what order?

From what I can see half the car needs dismantling to get in!!