I imagine breast pumps are already zero rated for VAT....most medical/ safety/ desirable equipment and food is.
The article actually says that it is maternity leave that would encourage more breast feeding. We are lucky to now have that in the UK so I don't think there is a problem to fix. Anyone who is physically able, and wants to, already ought to be able to breast feed - there don't seem to be any financial or practical barriers put up by the state.
I am pretty certain I was even loaned a breast pump for free (or only nominal cost) by the NCT but that was years back.