Do you have SCITTs in Scotland? They will sometimes offer part-time options.
I'm currently a PGCE student, although I don't have children.
The key will be the accessibility of placements and the support you have available.
For my last placement, I was expected in school by 8 and had a drive of an hour, minimum (often 1.5 hours in the evening). My current placement is closer (about 35 minutes door to door) but finishes later and I'll be expected to stay for meetings after school twice a week. This means that I may not be getting home until 6. I am still expected in school for 8. I'm not complaining about the hours I'm expected to be in school (although the last drive was horrendous) but just to make you aware of the hours you could end up being out of the house for.
I'm Secondary, and I accept Primary is a bit different in that you will have more schools in a smaller area, but also there will be more trainees on a primary course (usually) and schools can accommodate less trainees as they are smaller.
I also agree that there is a lot of work- whilst on placement I was regularly coming home from school, having dinner, then working another hour or two in the evenings. I was also working at least one afternoon each weekend (often more). My placement school was quite good in having shared resources you could adapt, and my mentor wasn't too demanding about when he saw lesson plans- if you have a mentor who insists e.g. on lesson plans 48 hours in advance, or you making all your own resources, the workload could be even more.
A lot depends on the structure of the uni course- e.g. for my assignment this term we had to do lots of observations in school (outside of subject area) meaning I lost planning time in the school day. It also depends on how time consuming your uni admin is.
Most unis will take into account caring responsibilities up to a point, but they also do expect the course to be a high priority, and you to be able to e.g. drop everything and go on a school visit this Friday where you have to be at a school half an hour away by 8am. We also only get a week's notice of placements, which makes it hard to organise your life.
I know this all sounds really negative, but the workload is doable (if you are not a perfectionist), but it's just making you aware of the logistics you will need to manage.