I've put dynamat all over the bulkhead and inside the hardtop on my 110 - it's really easy to apply and stays stuck - not sure how good it is at soundproofing yet, though...
I'd put
this stuff on the inside of the bonnet and the roof - it also sticks fairly well and is fairly easy to apply, although a hard roller of some sort makes it easier to do.
What diesel engine are you fitting? My Td5 had lost its
acoustic cover at some point in the past - I got one of eBay and the natural soporific diesel clatter has been deadened down quite a bit as a result.
I've certainly noticed in the past that filling the footwell with bags etc. has a huge effect on engine and road-noise, so I think a lot of it comes through the bulkhead - decent thick floor-mats and soundproofing over the transmission tunnel definitely make a difference.
Headphones (as previously mentioned) or just an acceptance that you're living the dream of Land Rover ownership are probably the most effective solutions, though...
