Kel
babe, I know how frustrating it is to have sleep problems... you desperately want help but no-one seems to know how to resolve it or IRL people just tell you to CC/CIO cause it worked for them, or "they've got to learn".
So you said she might sleep up to 40 mins.... does she not nap at all most days or does she sometimes have short naps during the day? would she have just one or more? Does she tend to sleep in the car? the pram? Or only the sling?