I asked my m/w for a detailed, 20 week scan. she said that she would put in the request at the hospital, but that she thought it was "unlikely" that i'd get one. A few days later, my appointment came through - I get my scan on Wednesday
One tip about dealing with the medical profession- you cannot "demand" any kind of treatment: although it should be provided free of charge, we as patients cannot really challenge how resources are allocated (although of course that's changing due to case law on things like fertility treatment, gnder realignment etc under human rights legislation). So forget "demands".
Bear in mind that the medical profession think in terms of "liability" of the NHS Trusts (and, in the case of individual practicitioners, on their own professional registration). If something goes wrong, then they can be found liable for negligence (or professional misconduct).
Anyway - if you ask to be referred (or for a second opinion) for ANY treatment and that request (not "demand") is refused, then if something later transpires to be wrong after they have refused that reasonable request, then they are leaving themselves open to liability and they don't want that!
What I'd recommend, girls, is that next time you see your M/Ws (or make an appointment if, like me, you only see her every 6-10 weeks!), ask them sweetly to be referred for a 20 week scan. If necessary, make up some vague story about your brother/sister-in-law/mother-in-law having e.g. a bowel/heart/whatever problem and that you're a bit concerned about the baby inheriting such a "defect". They might ask you what the problem is, but just say you're not sure, but that your mother-in-law said you should mention that your husband or his brother/sistercousins had bowel/heart problems as a baby
And don't worry about them checking your story - they do not ask for personal details because, due to patient confidentiality issues, they are not going to get the fictional bowel/heart problems in the medical records of the said sister/cousin/brother out to look at to catch you out
If the MW tries to dismiss your request for a scan, say firmly that you'd like her to write on your notes that you requested a detailed scan and that she refused to refer you. This should prompt her into a rethink. If not, ask her if there is anyone else that you could make your request to, if she is refusing to refer you. Persistence is key here, but hopefully, the m/w will refer you straight away.
I know, it's kind of "cheating", but if you feel "cheated" out of the same care as your counterparts in other parts of the UK (yet are paying the same in national insurance contributions), don't you think you're entitled? It's awful that we have to be made to invent some vague story about needing a detailed scan - and normally I wouldn't advocate "lying" - but I also think that there should be a way round an unfair health system which makes antenatal care a postcode lottery and this is my suggestion.
This is not us "cheating" the NHS out of money, but reclaiming what is fairly ours, as a right, as pregnant - SCOTTISH - women. It's a disgrace that we have to, but we don't make the rules.
Please let us know if you use this tactic and how you get on.