Hello arcane, I think you have the makings of a fab mum. There have been some helpful tips so far but I'll wade in with some practical stuff that might help.
1st of all, it's never too early to check out childcare costs in your area to get an idea of how much it will cost and what is out there for you to consider. If you get an idea of how much it will cost, the hours you can cover, then the work pattern you think would be feasible for the end of your maternity leave will be a bit easier to work out. Whether it's full time or part time, it's useful to get an idea as to how much the cost of a nursery is compared to a child minder in your area just to see how it all fits in. I've not used this website so can't say how useful it is but it's one source for you to search childminders.
Check out <a class="break-all" href="http://www.turn2us.entitledto.co.uk/entitlementcalculator.aspx?ref=www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CD0QjBAwAQ&url=http%3A%2F%2Fwww.turn2us.org.uk%2Fbenefits_search.aspx&ei=kGZkUfzXF8LA0QXbh4GACQ&usg=AFQjCNHQq4I2IY0qrYivIFE_BT2yzJuV9w&bvm=bv.44990110,d.d2k" rel="nofollow" target="_blank">this website to get an idea on tax credits etc. If you have an idea of childcare costs in your area, you can input those details and get an idea as to how much you might be entitled to once you go back to work. I find this website pretty accurate for me, it's usually within a few £ per week in it's calculations.
I agree getting well stocked up for the impending arrival food/supplies wise is a good thing. I'd recommend not making any arrangements for any socialising for the 1st few weeks - just 'baby-moon' if you can as that's the best way to get to know your baby, and what they need. Getting to know what the cries mean, what makes them happy and content, when they need a bum change etc. So not having to worry about shopping for or planning meals while you are 'baby-mooning' knackered is sound advice!
Sounds like you will have some good support. That is half the battle, but make sure you know more about exactly what people mean by support. There is nothing worse than thinking you have support, when the person/people you are relying on have a completely different and frankly useless idea of what 'support is and how much they are willing to give. I have found that knowing where I stand, even if it means I don't have support, is much better than hoping for support that never materialises IYSWIM.
CSA - this is always going to be a bit hit or miss. If you know details such as DOB, NI, address, work address, salary, it makes the whole process easier/quicker. If you are missing this sort of info, it's best to try and budget on the basis that you will get nothing, and anything that the CSA do manage to extracate as a bonus. Leave it up to them to deal with the father, and don't expect a quick resolution if he is v reluctant to co-operate with them. They'll get him eventually so give them all you know when the baby is born, and leave them to it if possible. Easier said than done, but it's preferential to giving yourself more stress and hassle hoping for a quick turn around.
And enjoy your baby as much as you can. For all the hard work it is doing it all on your own, it's still awesome to be that little person's whole world and seeing that in their eyes whenever they see you. You'll see the world in a whole new way, and it's lovely seeing them experience it all for the first time. Good luck!