Out of interest, how much milk have you been expressing? For a baby this age 70-100 mls would be a full feed.
I usually pump about 40-60ml a day, slow going my boobs respond much better to baby

When I've been out before she's had EBM from a bottle between 40-90ml but it wasn't quite enough to get her off to sleep, she would nearly go off then the milk ran out. She has two sleeps a day so I'm guessing I may need 100+ml twice a day. I have a little stash but it won't last long and if I get too tired once back at work to and get over it like you said Barb I thought there may be a suitable alternative.

DD is FULL ON! That's why sleeps are precious