Update: I managed to fix a little of the floppiness with fusable interfacing... Just ironed some pannels over the sewed pannels. It's not as pro or as pretty if I need to turn it to repair again, but at least now the bag pretends to hold itself up...
I've started another little baggie fully interfaced and that's working like a treat.
And I got to try this gorgeous KIWI (!!!!!) soft cotton I got the other day... Pictures coming up