In posting here in hope that someone here may be a teacher/head teacher/Educational Welfare or just have experience/knowledge that may help me.
In brief. Myself and my ex have shared residency of our two primary aged children. 50/50. They live one week with me one week with him, alternating. Ex and I don't really speak, he refuses to communicate about the children or any related problem.
Anyway, I was given an Attendence/lateness report at the end of last school year and was shocked to find the children were being taken into school late by him 2-3 days per week, every single week! 
I spoke to the head teacher in September who wrote to me stating she had spoken to my ex and reminded him of the need to be on time. When this didn't help and lateness failed to improve she sent him a written warning examining it is important and how it has a detrimental affect on the child. He has refused to discuss this. Head teacher has said it will be monitored,
We have now had a whole term of this school year so before Xmas I asked for another report. The lateness has improved (he has moved so is living a 5 min walk from the school now) but is still regular. They are being taken in late 1-2 times a week every week. Reasons for lateness given as "overslept" and "alarm failed to go off" I don't know how he isn't too embarrassed to write that.
What is your experience of lateness? Is once a week going to be considered a problem to be resolved in some way? I don't want to be seen to harass the head teacher but to me, regular once a week lateness is unacceptable - they are never late for school with me. I'm going to ask the head teacher to write to ex again or send one of their standard "lateness" letters. Do you think that's reasonable?
Also, and this is where is gets a little complicated. I know they are being taken in late more often than is marked on their records. My step children go to the same school so even when my children are with my ex I am doing the school run for my step children. I see him taking our children into school as I am leaving, or sometimes still walking down the road with them. The school have said they need to be there at 0850 and sat at desks by 0900 for register. Anyone not present at 0900 is marked as late. BUT they are often still walking down the road at 0900 or walking in the main gates just past 0900 when they the. need to walk round to the back of the school where their classes are, sort bags etc and get into class. Basically they are arriving between 0900-0910 and for some reason they are not marking them as late! I just don't understand. Do you think they are fudging the figure for their own benefit/to stop EWO involvement or something similar?
It's having a detrimental affect on them as ex is shouting at them to hurry up and they hate being late as it's embarrassing them walking into class late. Sometimes they are 20-30mins late and the last week of term they were 1hr late as ex overslept! (He wrote this in the lateness book). Ex says he doesn't think being late sometimes is a problem, I think it's a big problem as does the school from the letter they've send me.
So, I want to apply to Court and get it added to our Court Order that he MUST take them to school on time or that he must call me if he can't and I will collect them from his and take them (I'm there with my step children most days anyway). But I need to show the court their attendance report to get this done. I need it done correctly and so do you think it would be unreasonable to ask the school to be really strict on their lateness policy for a while and ensure that get a late mark when they arrive late? I don't want them to think I'm crazy
and I'm not asking them to do anything untoward, just to stop cutting ex slack as it's not helping long term.
Thanks for any words of wisdom you may have x