I was able to replace these by removing the 4 screws that hold the lint "chute" together which allowed the 2 halves to be opened up enough to get my hands inside. The replacement doors go on with the beveled edges out and the springs on the left peg on each door. Start the peg with the spring into its hole then CAREFULLY bend the door so the other peg can be inserted in the other hole.
Easy job, took all of 10 minutes. Not sure I'd even bother if it happens again as all the doors do is prevent larger items from dropping into the trap when the lint screen is out, which isn't likely to happen, particularly if you're careful.