I thought I would write an update for all looking for the info!!
I had growth scans from around 20 weeks every week or every other up till 38+5. The consultants seemed like 100% on the accuracy of the growth scans when regularly done throughout your pregnacy.
My son followed the 40th percentile the whole pregnancy and was delivered on Tuesday by C Section 39+2 he was predicted to be born at 7lbs 7oz just days before he was born, he was actually 8lbs 11oz on arrival and got a smidge stuck!