Hi & Congratulations,
I had my son last July at St.Thomas'. Unfortunately I had a very bad experience right from the start of my pregnancy through to the birth, I won't go into detail, because it wouldn't be a good thing to do, but I didn't get to meet my midwife (S) beforehand, (I went through 3 because of change of shifts), they knew nothing about me and hadn't even bothered to read my birth plan. I also have to agree with the post natal care, I was appalled at how I was treated, especially after what I'd been through, I ended up begging my husband to collect me, and I had to sign a self-release form.
I would strongly advise you to hire a private midwife, right from the start. My friend did this and they built up a rapport over the 8/9 months and she was there throughout the delivery, she had the labour in an NHS Hospital, but her private midwife was with her throughout, she was apparently very firm with the staff about what my friend wanted and completely took over when she was giving birth, this made her experience so much better and she was looked after very well. There may be no need to pay out for a Private birth if you go down this route, if you end up needing a C-section it could get extremely costly.
Good luck