I've been working out where the vibrations are coming from in my car, and noticed that the metal behind the rear seat, and under the parcel shelf make a lot of noise. My question is, does it matter whether I put the deadener on the 'inside' (eg, directly behind the rear seat) or the 'outside' (eg, actually on the 'boot inside' of the same metal).

No.

Straight up. Nice.

Cheers,
Kaeser

Cool, thanks