Mosey, that sucks. The crack in your bottom mount does look worrying. The course of action I suggest for you would be as follows (similar to that already suggested but with a couple of important distinctions)
Run a 5.2mm drill all the way through the mount. It looks in the last photo like you should be able to drill right out the other side of the mount, which I would do if possible but your aim should be to get atleast 4 or 5mm past where the crack has occurred. Don’t use a 5.5mm drill, this would be good if you were using a fine pitch thread but the threads are standard pitch and a 5.5 will result in a very weak thread.
Run an M6 tap into the hole you have just made deeper.
Get a bolt is exactly the correct length, leaving around 1mm clearance at the bottom of your new deeper hole (or ideally you have been able to drill right through the mount in which case just get a bolt that just protrudes).
If you do this you will be bolting into at least 4/5mm of good thread, beyond where the crack has started which should reduce the stress on the crack and with luck, your fork will hold together just fine.
Obviously, then check the forks every time you ride. Good luck whatever you choose to do.
