Mine had no cores left and the front to back pipes were leaking. My local place where everyone sends radiators to be recored is:

http://www.kempstonradiators.com/

Depending where you are you may need to find the local equivalent.

Anyway they were very annoying people and patronising and said some line about being unable to recore the radiator which I still don't quite believe.

BUT, £780 and two awful journeys to drop the car off and pick it up again later*, they did the following:

MADE a brand new radiator to fit, found the pipes were leaking at their union with the holdings tabs, and soldered them up and repainted in fuel tank paint and pressure tested them in a special tank to make sure they didn't leak.

I don't have the car any more, but I can't help feeling it was much better than a second hand rad from Yahoo Japan.

* Got caught speeding when I picked it up for first time in life.