It's a difficult one Sallysmum. However, I would imagaine that the person is genuine but I'm not sure why he/she can't exchange info by E-Mail, unless they don't have a scanner, which would make it difficult.
Also, because of the nature of our hobby, it's not so difficult for someone to find out our addresses. We advertise ourselves on web pages - names, parents names, where we live, where we were born, our ages etc.
If you are sure it's a genuine relation then why not go for it as there may be a genuine reason for wanting to use your address.