I finally finished installing the underbonnet sound insulation on my 2010 TDV8. Its only taken me 6 months. Fortunately I haven't driven the car since April so the time to do the install has not been a problem.
Fitting the Dynamat material is not a quick few hours to accomplish as you need to make patterns if you want a neat installation.
After removing the original underbonnet felt material the first task is to install Dynamat Xtreme material which is a bitumastic material with a silver foil outer layer. I recommend cutting this into smaller patches for a given area as it is very hard to install in a single piece. After the Dynamat Xtreme the next stage is to fit Dynamat Hoodliner which is a foam material with a silver foil outer layer. Installing the Dynamat Xtreme and the Dynamat Hoodliner adds a few kilos to the weight of the bonnet. It now closes with a thunk rather than a clank as it did originally.
I used the back side of a desert spoon to make sure the Dynamat Xtreme was pushed hard against the bonnet metal rather than using a roller. Just make sure that you don't drop the spoon like I did and lost it in the bowls of the engine bay. I might find it one day.

At the same time as fitting the Dynamat sound insulation I fixed the problem of sagging original underbonnet felt at the rear of the bonnet. This involved drilling 4 holes and fitting additional Christmas tree clips.

The only task left now is to find some black duct tape to cover the shiny silver of the Hoodliner which is showing at the front of the bonnet.

Looks a neat job...but I usually remove the sound deadening to hear more of the engine....depending what car I have

*Note to self...remove sound deadening off Range Rover  Steve.