Eurocar parts sell the radiator for just under £150 with free delivery.
http://www.eurocarparts.com/car-radiator
Normally a vehicle radiator is quite easy to replace – to remove; drain the system, remove the hoses (from the radiator), remove all bolts securing the radiator.
Replacement is simply the reverse of the above.
It is advisable to have an assistant who can take the weight of the new radiator while you are fixing it in place.
Doing it yourself could save you around £150.