Again thank you all for your interest and guidance - I have followed the advice that the majority of you have suggested and erred on the side of caution. I am sticking to my gut instinct for now, but have suggested to the third party that it would be better for the family member concerned to make direct contact with me first to clarify the situation, before I send anything on.
When I was first contacted, I was told that this person was researching on behalf of a friend, I didn't think anything of it at the time, but on checking the email address it certainly put doubts into my mind, as it suggested to me that it may well be linked to a business, (possibly a professional researcher) and that's what I am not too happy about, especially if they use some of my material for their gain.
Anyway, again thanks to you all for your help, it is very much appreciated.
Doric