I think it depends on what time you have your little one if you have them in the morning they can stay all day however if it’s the evening they are not allowed to stay over night so won’t be long after
I had my little one at 11.18pm my partner stayed for about half hour before driving home and came up at 8am and stayed with me all day
8pm x
I'm sure my other half was allowed with me until around 10pm ish xxxx