DD is 6 mo, started on solids, still feeding about 9/10 times a day. Her feeds are very quick and she is very distractable. At home I feed her lying down on the bed, out and about I have to find a feeding room or quiet corner.
She has gone 6 hours at night without a feed a couple of times, 5 hours about 3 times. She usually wakes for food every 3 hours and wakes for her first feed at 9/10ish (bedtime is between 6 and 7) (She also wakes for her dummy, wakes because she wants to sleep next to me...you get the picture)
We have a bedtime routine and she goes down awake, albeit with a dummy. Often she is actually hungry when she wakes (although not always, but I can never tell until she is latched on)
Now here is my problem. I have an evening out booked on Saturday. I didn't imagine I would have a problem going out at this point and even naively thought she would be sleeping through the night. (We can co sleep to deal with the rest of the night wakings for now)
I now don't want to go as I worry she will need me and will cry for boob. DP will offer her milk in a cup (she is a bottle refuser) but I fear this won't be enough (she often spits a lot out).
How do I get her to sleep longer without milk? I currently give her some of our tea at half 5, then its often straight into the (fairly short) bedtime routine.
Do I offer her tea earlier so she is still hungry for milk at bedtime? Have a set feeding routine? I am fuller in the evenings than the mornings at the moment so think it is reverse cycling. 
Oh and she is teething atm which doesn't help.
Thoughts and advice appreciated, thank you.