malinois:
you say you know 'many IT contractors who work a bog standard 9-5, short commute, 6-12 month rolling contracts, and are pulling in £500-£800/day'
Can I ask where, and doing what? I'm an IT contractor, and only tend to see those rates advertised for contracts in the City - which expect you to put in a lot more than 7 hours a day (with a typical London commute of 1 hour each way for most people).
I'm genuinely interested - DH and I have been thinking of re-locating in order to reduce the commute and get away from London over-crowding, ideally without losing too much income. Probably a bit of a pipe-dream, but I'm wondering whether I'm missing an opportunity somewhere! 
Sorry to hijack, OP!
To try to make up for it, I'll give what advice I can! I'll offer that if you an aptitude for programming, it's a great job: interesting, creative, and with a pretty good pay/stress balance. On the down-side, I don't think it's the most flexible job for combining with childcare. Since it's so male-dominated, employers aren't used to having to deal with flexible working, and often aren't willing to risk it (except for very experienced /valued staff - and it would take you a few years to get to that stage). On the plus-side, if you do want to move into programming, you wouldn't need to retrain formally. A degree of some kind is useful, but not essential - and it certainly doesn't need to be in IT. Experience is the key: commercial experience is best, but anything where you're delivering software to a client will allow you to start selling yourself to an employer. You could teach yourself to program, get some voluntary experience (it's quite important that it should be for someone though, and have a defined purpose). Getting your first job is the hard bit, but then after a couple of years in a permanent job you would have a lot of options. As well as reducing the cost of retraining, this would also mean you find out very quickly whether you enjoy programming.
Good luck, whatever you decide.