Today so far is going better. Enya hasn't vomited again since I gave her an anti-emetic yesterday. She could barely keep her eyes open for lunch yesterday, in fact I think for the last spoon her head was on her shoulder and eyes were closed (side effect of the meds). Although she is not very interested in food, she has at least eaten 100g per meal. I've tried to avoid milk as far as possible, but after 140ml of the rehydration solution she fought so violently I had to give it up, so we're back on milk.
In the last 24 hours both girls have developed very runny noses and Enya has also got a matching wet cough, so now I'm thinking the vomiting maybe has something to do with that. Babies can't spit out their secretions so they swallow them and the secretions can make them nauseous and vomit. At least they are both cheerful and are right now playing together on the kitchen floor.
Now I just need to make them something bland for lunch.