I was also advised by my midwife to seek out a liquid iron supplement as in a liquid form it is much more easily absorbed than iron in tablet form. I see you are in Melb, me too! My midwife directed me to a pharmacy called Dartnell's Pharmacy which is in Surrey Hills (VIC), they make up the supplement there. (I also picked up a post-partum tonic there full of all sorts of goodies for after birth!) They will take orders over the phone and send some to you if you can't get there.

I also took my supplement with OJ as vitamin C helps with iron absorption.

BTW - I didn't notice any problems with constipation with the liquid form.