Whoknows well you wouldn't be in awe of my actual house, decluttered or not it still seems extremely messy and I've just noticed a lot of cobwebs and greasy ceilings
now that there are less objects to distract the eye!
resorted to putting dd's non-essential (I am talking hoodies] laundry in a sack and hiding it rather than doing it, she has just too many clothes in her room atm, more than enough to get thro holidays
decided on Christmas eve pud of meringue with cranberry clementine and pistachio from bbc (random choice)
and someone is giving me a cheesecake!
just cooked boiled potatoes, tomatoeless meatballs simmered in stock with parsely and lemon, and cucmber on side. For pudding we had some canape custard tartlettes (from M & S) jaffa cakes and pomegranate seeds 
bought lots of christmas veg from greengrocer, so that chore is done. I think he is open on Christmas day though, such is London, so I don't need to worry really...
SC 13-16 is three years. Could you think of way to fund International school for that time, if this is going to continue, just to get dd back to confidence and engagement? I would just be worried that she is going to give up entirely if she isn't fitting in academically to "their" timeline or expectations. After all, it is just one system, in one country, the rest of her life there will be students of all nationalities and education systems mixing together in uni and training, if they get to that point. Some of the children who went to liberal schools still end up doing well academically.
Dd was very uninterested in academic excellence till recently; she had several friends acquaintances who as far as I could see were swots and extremely conscientious, this has rubbed off on her [up to a point] and she has suddenly started really pushing to do well in Spanish and Maths and her attendance has leapt to 100 percent (she wanted the Certificate) She has just won a prize for academic progress across all the levels, but as far as I can see she still moans how boring Geography is and how the science teacher is so bad he wasn't allowed to teach GSCE year. But I always feel she is being allowed to motivate herself and find her level and that is working to some extent because it is a very creative curriculum up to GSCE, so they are always learning on some level even if it is not an obviously academic standard that is being set.
I suppose it is what you want for Dd in the long run. A vet? A doctor? or a journalist, an artist, a writer, a business entrepreneur. Some of these things require excellent academics, others are more about developing your confidence and ability to relate to others, which I suspect your dd is well set to acquire whatever her grades. It is a battle to make someone something they are not. What do your UK relatives suggest? Any long view there?
Whoknows recovery from operations can take so much longer than the surgeons suggest, your poor MIL.