Phil, I've not tried any of these (I'm not a massive fan of kidney, although I like the Pukka Pies from chip shops in the UK! It's more like a kidney gravy than chunks of kidney), but I had a quick look on a couple of websites for you!
http://www.channel4.com/food/ and
http://www.bbc.co.uk/food/ both have recipes that may be of use. Use the search box and I think you get 6 on the C4 site and 4 on BBC!
Thanks Neil, there's a couple of recipes I'm going to try. Funny thing though! none of the recipes called for soaking the diced kidneys in milk.
That really cut's down on the uric acid taste, just soak them for a few hrs. Twice. discarding the milk each time.