Cant see why a pump wouldnt be allowed, no sharp pieces, and other eletronics allowed on board. Regarding breast milk the DAA say:
"Can I bring baby food/milk through security?
Yes, baby food or food for people on special diets is exempt from the new regulations. Passengers are allowed to bring these items through the screening points in the quantities needed during their trip.Passengers may be required to demonstrate that what they are carrying is real and for genuine use and not something less innocent."
we are travelling in 2 weeks and bringing pump and expressed milk.