mum2b1, further to the early scans, I recommend FMC (Fetal medicine Centre) very highly, as does most of Mumsnet. You can get a nuchal scan for about £150 and an anomoly scan for £300 or so (I think??). I had a nuchal there with both pregnancies and the price is well worth the superior medical treatment you will get there. You can at least walk out of there at 12 weeks with peace of mind knowing that your baby is healthy, developing normally, etc. Chances are you aren't offered a nuchal in Sunbury anyway (unless you are say 39 or older).
If I were you, I would refuse all medical treatment, and then go get some blood tests, scans, etc. privately. That was you actually get the medical attention you need but all the while putting pressure on the PCT because it is their job to find you a place. And as far as they knnow you have not received any medical treatment.
It is sooo important that you refuse any medical treatment from St. Peters. Do not let them register you with the midwives even for an initial chat / bloods / urine test / anything.
Oh, and the urine tests they do routinely for pregnant women (checks for sugar, protein, etc.) are stick you can buy off the internet.
I wonder if there is somewhere that you can get a list of all the routine test offered to pregnant women? Iknow some of the blood tests test for specific things at aspecific times. I can't remember what for and when as I am certainly no doctore. But, I bet this information is available somewhere.