Aftermarket double din head unit fitting advice

[Topgearskin]

Evening all. Nice to be hear, lots of great posts!
My first post was sent to the generic site, so I'll try again in the custom section!!

Having bought a 14 plate custom last week I decided to soup up the ICE with a reverse camera, sat nav and DVD player.
Bought the fascia and wiring, as well as a generic head unit.
All was going well....
My first issue is, I can't get any power to the head unit even though I've bought a custom specific wiring kit.
The bigger problem is the space left by the OEM unit. It's not big enough for the double din size unit. There is a bizarre plate with some very pointy screws which appear to do nothing other than prevent me fitting adouble din head unit!!
Really interested in any advice or guidance. Has anyone successfully swapped out the OEM for aftermarket? Did you have to cut away the dash support.

Thanks in advance

[DrDeAtH]

There was a thread on how to do this. Have a search through the customising section...