Current UK guidelines say a minimum of 300ml which is about half a pint, it used to be 1 pint so your HV is a bit out of date.
Her bedtime bottle gives her a bit over half of what she needs so with her cereal milk and some cheese/ yoghurt in the day she is getting enough I think.
Keep offering the sippy cup, it does take them a while to get used to drinking milk from it but if she likes the taste of the milk, it will improve. We kept the bedtime bottle for a while to make sure DD got one good milk drink a day, there is no problem with keeping that bottle, just make sure it's drunk quickly and teeth are cleaned afterwards.
Laura