As of 01 October 2007 it was made illegal to sell knives and certain other articles with a blade or point to anyone under the age of 18 here in the UK.
So the question is - How can a seller here on eBid selling such items ascertain the age of the person they are selling to?
The responsibility to comply with the law rests with the seller. As I read it the fact that eBid acts as a venue for the sale does not make them complicit in any breach of the law - but then I am not a lawyer.