Wendylon- you sound stressed and resentful. No offense meant. I feel and have felt the same way many times. At this point, I say yes, let him miss appointments or be late. Also, if he is clueless about the half term thing then he is just clueless. (I am as well since I am in the states. lol) In a nutshell, if your H has to deal with the actual natural consequences I guarantee that he will start to change his habits. Secondly, by trying to protect him or take care of him in the end it is just pissing you off. Not good. Let it go. Let him deal with it. If it were me, I would get a big calendar and put it up with things clearly marked. Tell him you are doing it and put it where he can plainly see it. Then- if he still doesn't notice the weight is off you but so is the responsibility. Suddenly, there is no one to blame but himself.

Good luck and hang in there!