Saturday I decided to go ahead and do the sound deadening.
There's lots of vids on YT about how to remove the trim panels and as long as you are gentle when pulling out the poppers you should be fine, although I did buy a pack of spares off eBay, and needed one of them.
Here's the boot with all the panels removed:
I removed the silver struts you can see in the first pic before I carried on.
I then went round and covered with sheets of this: https://www.dodomat.com/coll