As long as they are getting enough milk through the day, so judge it depending on whether they’ve had enough milk or not. I think they should get between 150-200ml per kilo of their weight. My little one will take her last bottle around 7/8 and sleep through from around 9/10 - 6/7. She was the same when I made her another bottle would only take a little so we just judge it whether she’s had enough through the day or not and if she needs more we will give her the extra bottle before bed. Hope this makes sense.
Some babies can start sleeping 11-12 hours at night from about 6 months old, so I'd say last bottle at 1900 ish would make sense at that point, I'm no expert though!
My little girl is 9 weeks old and she averages about 7/8 feeds within a 24hr window. She has her last BF at about 730-830pm and then I wake her approx 5 hours (1am) later for a feed, then she usually wakes me about 4am for another little feed and then she sleeps until 6am. She sleeps again and I don’t then feed her until 8am. During the day she averages feeding from 3hrs between, to going longer at night time x I am working towards loosing that early morning feed. But at 9 weeks they are supposed to be able to go 5 hours at least from being put down for bedtime. She went 7.5hrs the other day, which was insane. Hope that helps
Our little one has been quite similar with the sleeping through the night! Most nights she has her last bottle anywhere between 7:30 & 8:30 & doesn’t wake til 6:00am, feeds then sleeps again for another couple hours. I think as long as they’re getting enough calories throughout the day then it’s okay.