Thanks for the replies... I'm desperately trying to get a second opinion before they stick her in this thing! It's not easy here in the UK as all the consultants are both NHS and Private and so you end up going to the same people who aren't likely to contradict themselves!
On all previous assessments she had an US but the latest decision was based on an X-ray, which apparently isn't as conclusive.... so we're eally hoping for further assessment before any decision about harnesses or surgery is made.