Get in there! I think I'm there on the same day.
I don't know if they've always done it, but last time they told me my blood went to St Thomas's hospital, which was nice, as my kids have needed blood from there.
Oo I did that one. Thought about it for many years, never bothered to do it. HKFC said he thought it would be good if I did it, so I did. So why don't you do likewise - just make the call now, and book yourself in?