anyone any advice re my 6 wk old who was feeding beautifully with avent newborn teats now v reluctant to take bottle and taking v.little resulting with bad wind. have changed to no.2 teats and tried variflow to no avail. do know about dr browns but am reluctant as don't see how i can make up feeds out and about with these. was wondering if any other make of variflow teat compatible with avent bottles. any advice gratefully received