I'm not planning to go on the Barra fly-in, but there may be someone who is. It's worth asking around!
I often find myself flying a couple of empty seats on trips where I'm sure others would love to come along!
I looked to see if there is already a listing for Barra 2004 at
http://www.thehangar.co.uk/flyindex/main.php - but there isn't (yet).