At least this is experience i can now learn from. Mind you the damage was already done before i even realised there was an issue, im just happy it didnt get so hot that it could of siezed the engine. 
 
Thank you everyone for all the help, you all have helped increase the learning curve that much more. 
 
Ill post up the extent of damage once i find out

nick12

ah, the wonders of the world's most complicated cooling system.

 
LOL its not that f**king hard! :)
Spent about an hour draining and refilling Josh's SW20 turbo yesterday, as long as you have the car up in the air at the back and you bleed the system correctly (i.e, radiator bleed, HC bleed and filler cap) then you will be fine!  Due to the sheer size of the system, burping it every few days for about 2 weeks afterwards is a good idea as it can get rid of the slightest bubble in the system that would get forced around by the water pump.
 
The worst thing you can do to them is stick cold water in an overheated engine... Then wonder why your car wont start LOL.