CRL was 2mm, which I think dates the pregnancy at 5 weeks 3 days, as opposed to the 5 weeks 5 days by my dates. So it really is marginal. Its a private clinic, so I think they are quite thorough - she couldn't give me all the information they normally do, which I think is part of the reason they want us back. They're not charging for the second scan as they said they like to be able to give a lot more detail than they were able to today.