This is me, OP was my Dad paraphrasing. Thanks for the tips Goblin634257 and ak57. I've already had a couple of hours talking to some solicitors for general tips. I've done as advised (when I've remembered) and noted down things that might seem relevant. I'd have to bring together texts and calls (auto recorded on my phone for the last few months at least) as well but there's various things in there when I've been surprised by how things have turned out.
Now, my aim isn't really to gain custody and take the kids "away" from her, I just want to make a plan and stick to it. Stop making changes that seem to be for Mum's benefit rather than that of the children. I often feel forced into things ending up the Mothers' way, which I don't always feel is what works out best for the children.
"I'm not looking for a partner; if I found one I'd be with them a good while before they go involved with the kids or us living together" - 10 days later she's with an old friend, after a month mostly living together, 6 months since walking away from me they rented a place together. Kids both knew soon after the start. I was informed that now she felt it important to introduce the new partner asap in case the kids/him didn't get on.
"I'll stay close" - New house with new partner is more like 20 miles/a good half hour away. New partner doesn't drive, so can't get home late after shifts, hence moving to his town. She doesn't drive so I do at least 70% of the trips to get them/drop them off with her. Her turn Christmas/Boxing day? My problem - no trains, for example.
"I hated being swapped over in a car park between my parents who were barely speaking" IF they are brought down to me, I have to meet them at my local train station rather than they be brought to my door (10 minute bus/taxi ride), she come in for a cup of tea and a chat etc like I do at their end - because the bus is 40 mins later than the train gets in. So -I'm- bad for not seeing why I should come and pick them up as they'll have to "stand around for nearly an hour" (in the middle of town, where they could have lunch, shop, do anything)
The move away and lack of transport meant nursery 3 days a week was an inconvenience for her. 2x3hr round trips a day on the bus/train make it a bit hard to work as well. So August this year, we had to change nurseries on her weeks. Current (awesome) nursery couldn't keep the kids if they were coming in one week each and one not, so I had to move them elsewhere on my weeks too. August they started at her new nursery, October in mine as the old nursery kindly did support them only coming in one week out of two for a while, till I got a new place. Originally we were each paying for one child at one nursery, but we've now ended up being each invoiced for both children. So there's money "issues" involved where before it was simple enough. Come the end of November and Mother's decided to give up working entirely. Primary reason given was it being too expensive to send them to nursery, and she'd end up with more money each week. As my disgust at this surfaced it suddenly morphed into being a stay at home Mum and to spend more time with the kids. She was working/sending them to nursery 3 days a week (a different three to the days they were going at the old nursery) So, no more nursery on her week. And no more responsibility to pay the bill for her daughter while with me, like we'd been doing. And no more work! C'est la vie!
This is probably getting a bit TL:DR for most so I'll sum up that we're kind of at a head here, with her wanting to have a 3/4 day split of the week, while I'm happy carrying on with something that seemed to be working for the kids and for me, i.e. having a week each with them. I'm stuck because she's moved further away and can't practically get to a school further than a mile or two away from her, and we need to apply for (very soon, ideally) a place for our boy to be in school from September.
Changes seem to happen rather often and I can't work out the motivations behind lots of them - at least from the kids' point of view. I just want the best for them but struggle to find a happy ground. She wants them during the week every week. If I picked them up Friday after school and dropped them off Monday morning, I feel I'd have zero involvement in their school lives - I don't -want- to just be there for weekend playing around with no specific agenda, I want to be part of the everyday stuff as well - which I why I feel one week on and off works well for both parents... it's just made a huge chunk harder since she's moved away from where they were born, have grown up so far, and have their grandparents - with no car to easily travel about in.
She's refusing to move; should I go and move to the dump of a town they live in? If the proposal for one parent to keep the kids during the week and one at weekends is fair, could it not be flipped the other way, i.e. me have them and they go to a school nearer to me/my parents? Nope? No, because "I'm their Mother". As a caring Dad who wants as much involvement as possible in the upbringing of his children, children who evidently have a great time with me, am I that much less important just because I'm the Dad not Mum? I'm more told how things will supposedly change, than be involved in the decision making at all.
End overly long rant..