Light leaks, or shoddy developing?

No leaks. I surrounded the door with electrical tape. The development still needs honing however.

Well, now you know you need a foam kit. There's a member here who sells better quality foam kits for lots of different cameras and generic ones that can accommodate nearly any camera. I've used his kits, some years ago, for a couple M42 SLR bodies, and had no complaints, though the member name has slipped my mind.