Need impartial advice about ex behaviour - I'm furious - reasonable reaction? How do I proceed?

[Twatexagain]

My ex is a bell end, does the minimum parenting possible, he gets every 2nd weekend for an overnight.

Dds are 6 and 8, their dad wanted them through the week instead of the weekend with it being the easter holidays.

Dd (16) came back today from being out and told me she saw my 6yo standing alone outside bus station toilets, so she waited for 6 minutes until dds dad came out the toilet, 8yo came out after a couple of minutes too.

Dds came home at tea time and were talking about meeting dd, it comes out he often does it, leaves them outside shops, and sometimes locks them in the house while he pops out to the shop if he runs out of milk or something, the shop is about 10 mins from his house so he would be gone about 25 mins. (Also transpired he went away for a weekend and left his cat alone for 3 days as well, but that's a different matter).

I will say I do have a tendency to be over protective of my dc (one of my dc died some years ago) but I need to check in that I'm right to be furious about this, am I? Or am I being over protective?

How do I move forward with this? He doesn't react well to anything vaguely like criticism, but I can't leave my dds in an unsafe environment.

Any advice appreciated.

Would you prefer he took your 6 year old into a men’s toilet with him? Not ideal either way.
he can’t be leaving them in the house for 25 minutes alone without adult supervision.

Leaving your children alone in a bus station of all places and at home is neglectful and dangerous. You’re not being overprotective, they’re far too young to be left alone.
Can you be sure he doesn’t leave them alone when he has them overnight? Maybe popping to an off licence or pub when they’re in bed ?
I think you need some legal advice. Found this online. Scroll down and it has some contacts. https://parents.actionforchildren.org.uk/home-family-life/family-relationships/worried-my-child-isnt-safe-other-parent-safeguarding/

Thank you, I know taking her into the toilets isn't exactly idea either, but preferable to leaving her outside for over 5 minutes at a bus station.

In all honesty I can't be sure he isn't leaving them asleep, I didn't think he would be leaving them to go out and get basic things he should have in anyway considering he rarely has them, he should have plenty of time to get shopping in.

I had a read of the link (thank you) @Andthereyougo and it says to talk to him calmly, however when I've done that in the past he just shuts down and walks away and never discusses it. Or I'll say something and he will come back with "well their hair wasn't properly brushed last time I picked them up" (directly after a sports club). He is impossible to communicate with.

It's really hard to navigate, however my daughters come first so I'm going to have to.