I am trying to fit Bluemels mudguards for the front wheel. I am a bit unhappy about tire to mudguard clearance, but I can't move the mudguard more away from the tire because the bracket is touching against the ring that is attached to the end of the tube where the fork comes out (feel free to replace this description with the appropriate name :D). Would it be safe to just put some sort of spacer on the bracket screw so that I can pull up the mudguard further? I can't unfortunately replace the bracket because it is preinstalled on the mudguard.
How long is the mounting bolt? I'd try adding a couple of small washers between the purple and the L bracket.
You can also file off the top of the L bracket for a few millimetres more clearance, or carefully bend it aft to make clearance.
Another option is to replace the L bracket completely with a fabbed one that has better angles for your bike.
Mudguards / Fenders are not high-precision instruments, so you can be a lot more adventurous with your alterations.