The address is a private house from what I can see on Google Maps.
This isn't unusual as it is/was the home address of the domain registrant. Whether it still is - who knows, Nominet don't bother validating .org.uk domains much unless someone complains about one.
I would however point out that .org.uk domains are specifically intended for non-profit making organisations/people. Even if the guy is 100% genuine, he shouldn't be using a .org.uk domain to sell anything for profit unless he's a registered charity.