Hello @SupportWantedPlease sorry you find yourself here but hope it's helpful.
I know some schools are able to offer supervised meal or snack support, unfortunately ours wasn't able to do this. It was probably a blessing in disguise as my dd was very talented at discarding / hiding / 'pouching' food so she didn't have to eat it, and it was hard to spot even for us where we watched her 100% of the time while she ate. The way our school was most helpful was in terms of flexibility with attendance, she was off completely for a few months at the start, then went for mornings only for another few months, and now she is there full time but comes home for lunch everyday. It's been a gradually improving situation in terms of her attendance, in the early days she found a whole week hard going and to be honest she was so unwell she wasn't capable of learning at that time. The head of year has met with me and my dd regularly to check in with how things have been going, and they have been open to suggestions about how they support her.
My dd is very concerned with not appearing to be different from others, so she has turned down some supports they have offered like a quiet space to take a break, attending a ND girls group or having small group study time. I've found that quite frustrating to be honest because I think it would help, but she obviously has to feel comfortable and it's her choice around this at the end of the day.
In the earliest days my dd wouldn't / couldn't admit there was a problem with eating (she is a little better at this now) and so any support offered around her feelings related to eating was rejected too, and she was quite vocal about her feeling that we were just making a big deal out of nothing.
Hope the meeting goes well. It's hard to know what's going to be useful at the start, and perhaps the support she and you need will change over time. Good luck x