Several people have posted up concerning the difficulty in getting oil coolers and radiators in decent condition and new ones are very expensive indeed (oil cooler £440

). So I thought it would be worth looking at firms which manufacture pattern radiators and refurb damaged ones. These people
http://www.aaronradiator.co.uk/pages/motorcycle.html actually show an example of a ZXR400 radiator they have completely recored for £220+VAT - repairs are cheaper. Again it's not cheap but for this you are getting a pretty much as new rad for a damn sight less than OEM. They don't repair oil coolers but they will make a new one using your knackered one as a pattern for £200+VAT.
Maybe worth investigating if you're struggling to get anything decent from a wrecker and brand new is not an option?