I'd say Gavin's right and somebody has modified it and added the blocking diodes for better protection.
You can use the same driver transistors that are on your galaxy driver board
+1 to Ken's and Gavin's comments, i think the diodes are an add on, as when i worked on AP member Howzat (Ian's) howzat game, i had to put a couple of transistors into his game and it didn't have the diodes.
