The only place I know in the UK that actually requests copies of health certificates from breeders is www.champdogs.co.uk
I am sure if there are other sites and or places someone will be quick to correct me, but this is the only one I know.
Hope that helps.
Nicola - it doesn't matter what i say or do everyone has made their mind up already - even though no one knows me. I really didnt mean to offend anyone nor did i expect to be harassed.
http://www.coloradobasenjirescue.org/adoptable.shtml
Co basenji rescue has several young-ish dogs looking for homes. And those basenji/terrier mixes are adorable!