Just to pick up on a couple of things.
You can still use I.Ms after autumn legally, just not for the actual delivery of the baby.
One to One is not offering the same care as an I.M would really, as I.Ms can be chosen by high risk women (older, younger, late, early, big, small, VBAC, Twins, Breech etc). As far as I understand no support will be offered in a one to one capacity to "high risk" mums through either Neighborhood Midwives or One to One. Read this in the Guardian a while back, but please, somebody correct me!?
You can decline anything you like. The tests (yours and baby), vaccines, weighing and check ups are all offered. If they are offered, then implicitly, they can also be declined.
I chose some blood tests, but declined others. I chose to accept first initial weigh for curiosity, but only after a good old bond and only when I was going to be putting baby down anyway whilst I showered. After that, my I.Ms offered weighs and tests over the next 4 weeks and discussed any concerns I had, supporting me recovering from birth and establishing a breastfeeding relationship. I was signed off by my I.M and became then passed to the HV, who I sometimes visit for the book bundles! I don't want strangers in the house so go to a clinic for this.
Hope this helps.