Yeah Nan I agree with everything roller has said, you have to stand firm and use whatever leverage you can. Life stops until she eats, food is medicine etc etc. I used the 'when and then' technique with dd at times so 'when you've eaten that then we can go on a (v short) walk/ watch a film/ play a board game/ go to etc. Without eating her life should be completely boring/bedrest.
Also when she does start eating distract distract distract, talk about anything else other than the food (other than to say keep going/ another mouthful please).
My dd isn't great again, being off school really brings her down. The self harm is back as is some weird sneaky behaviours that I thought we'd seen the last off (hiding food, smearing etc) That said she managed a subway out Ystd, she used to love subways but has refused to go anywhere near them since the ED. She did okay with it although didn't eat all of it and moaned about one of the fillings I put in.
I also made her buy pick n mix in Wilkos and she had it for pudding (I helped her out with a few sweets 😉)
So as always up and down.