Seems to be BFS-KEF is vis Edinburgh but KEF-BFS is not
It seems to be a B737-700 both ways as when I reserved my seats there was only 26 rows.
Your booking
Date Day Flight No. From - To Depart Arrival
01/07/2011 Friday 5W532 Belfast BFS - Reykjavik KEF via Edinburgh
11:20 14:50
08/07/2011 Friday 5W531 Reykjavik KEF - Belfast BFS
07:00 10:20