I want to use the DNA way of identifying my dogs. I believe there are cheek swabs and  or blood samples. Which is the best way and where is the best place ,price wise to get it done.I believe this is going to be needed to validate health tests .Hope I've explained myself. Thanks.

The Animal health Trust do it. http://www.aht.org.uk/genetics_tests.html    mouth swaps are required. 

So do the KC http://www.thekennelclub.org.uk/item/463 I believe they are about half the price of the AHT :)

I should have said the KC do it.

If time is not an issue then the KC is fine but if you want it done quickly go direct to the AHT , unless things have changed it is the AHT that do them all anyway but they prioritise their direct customers.