update
we have weaned the piglets today (3.5 weeks old) They are taking small amounts of creep feed and were giving them milk three times a day.
Mum is now eating banana and spinach smoothies and is also eating the spinach "raw". She is still vomiting when eating and drinking, not every-time and never the full amount as she has eaten.
We did see a slight improvement after the Tetroxy (but this could be because she was as high as a kite on a plethora of drugs) so might try her on a second dose.