Right, might seem a small update but i've just spend a little over the past 2 hours doing this.
Added a small fan to the heatsink and back of the glovebox to move a little air. Can't add a large fan as no room to anywhere. To make the whole on the back for the fan i had to go round my sisters to get a larger drill bit (did that a couple of days ago though)
Then when i tried to fit it back in, the fan was hitting the glovebox meaning the whole thing wouldn't go in anymore. Get a drill and steak knife and cut a hole in the back very badly. We are now left with:
(i thought the fan was hitting right at the back which is why i removed so much, turns out only a small amount needed to come out)
Just played halo 2 for a few mins, and when i checked the temp it was at a nice 48oC. Fingers crossed that's cured the overheating problem. When people are playing halo the glovebox will be open to let controller wires through so that should add to the air flow, when i'm just listening to MP3s it shouldn't be working as hard so won't get as hot.
Fingers crossed i'll be able to get everything glued into place soon, then once the screen is in the astra all i'll need to worry about is bodging the steering wheel controls