I hope I can help with this. My husband did 4 years at University doing biology when our children were little (they're not exactly big now but you get the idea lol) and now I'm doing my MA part time too. We have 3 kids currently aged 7, 4 and 3.
When I was working my hubby used to drop our eldest off at the childminder around his lectures (I worked 4 days a week, and we used the childminder all 4 of those days most of term time). I would recommend looking at childminders as they tend to be a bit more flexible with hours etc than a nursery. Having said that, I used the on-campus nursery this year for my MA seminars and working time and they were great too.
In my experience, you get the timetable at the last minute. I think I had a 10 day window to get everything arranged for my 3 for this year. I recommend researching ALL of the possible childcare arrangements you could possibly need to make. After school clubs, breakfast clubs, childminders etc etc, and then when you know, you can contact the ones that fit your needs the closest. Also, save up a term of fees, or make sure you'll be able to pay them as the fees elements of the loan payments are paid after the event. You should get 85% back though, so it's worth claiming.
The government hours are not restricted to mornings/afternoons. Most places are pretty flexible about when/where you use them. I used my sons' to cover a full day (9-5) and a morning (8-1). I've also used them previously at a CM, and at a private nursery to do full days. You can even use them for 9 hours a week all year round if you need to. You just need to check with the nursery/childminder. It's not just pre-schools. Also, if you're a student and your OH is working, you may not get free 2yo hours. I did for my middle DS as I was at home, but last year we didn't. Check that too.
It's a stress but it's always worked out in the end. There's always a way round it. Good luck! :-)