I've tried those stretchy step-in bras, called AaH Bras. Hopeless, no separation or support and after a while they dig in round your middle just as much as ordinary bras. I find M and S bras hopeless, I've never bought one from there that fitted properly even after the 'fitter' ran her tape measure over me. I've been fitted in Debenhams, too, and still not got a bra that was comfortable. At the mo I wear a Triumph underwired one which is bearable until about tea time when I have to take it off and go bra-less, not a particularly pretty sight but it's too bad. I have an elderly friend who never ever wears a bra and is proud of it but I'm sorry to say she looks rather round shouldered and droopy, not a good look although I admire her for taking a stand. I don't know what the answer is but I'll try that link.