Is it just me or is anyone else having trouble with the Avent variflow teats? My 17 week old dd has no trouble with the bog standard number 2 teats which she's used since 9 weeks but when she has the variflow ones, using number 2, she almost drowns! I've already decided to wait a few more weeks before trying again with them (after all now I've bought them I may as well try and use them) but just wondered whether it was something I was doing???