5mo BF baby won't take bottles when I'm at work

[PterodactylTeaParty]

Started back at work part-time this week. I'm gone 5-6 hours on days I'm working, and in that time she's only been taking a tiny sip of expressed milk. She's had occasional bottles for months and been fine with them, it's just more recently that she isn't interested and smacks the bottles away. (She feeds like crazy once I get home.)

Is this too long for a baby her age to go without milk, or is it ok? She likes to feed little and often when I am with her, 2-hourly or so, so I'm a bit worried about this. Is it worth trying a cup instead of a bottle?

I finally got formula into my almost 6m old in a sippy cup (the ikea one) while sitting him in a bouncy chair rather than holding him. He had also had occasional bottles then started refusing. Before that my mum had some success with an open cup. I also found that making the flow from the bottle as fast as possible helped - I poked a chopstick through the hole in the end!

Mine tends to get distracted when out and about and could go this long without feeding if I don't offer but then tends to wake up in the nnight to make up for it.