I saw an advert on ebay, that this company can cut you a red and 2 blue keys for 180 quid.
They need a couple of things, cant remember what exactly. I'll see if I can find the advert again.
The reason a replacement red key costs 800 quid is because they change the immobiliser, door locks, ignition etc completely. This company can simply remake a red key with the same immob code n such, hence why its so much cheaper.