I am post rectocele op and have never got rid of the constipation. I have a sachet every other day to keep things moving. Make sure you drink plenty whilst using it - keep a glass of water by you to sip when you feel thirsty.
Have you tried kiwi fruit?
Have you tried a 'transit test'? You can do this yourself by eating a load of sweetcorn and seeing how long it takes to get through. If it is more than a day or two, then you can work on eating things that help keep it moving. If your transit is slow, your stools get dried as they go through the colon and that slows everything down again. Progesterone slows smooth muscle down, so if you are pregnant or on the pill, this may make it worse. (Coffee is supposed to speed it up, but not in my personal experience - just get a headache
)
I have taken 3 movicol a day in the early days until it is all running smoothly.
Soluble fibre (fruit, veg, oats, pulses) and plenty of water are your friends. Bran not so much, as it dries out and slows things down in a slow intestine.
Don't forget to look up the squattypotty, pelvic floor muscles, and pelvic floor relaxation exercises.
Glycerin suppostories are good for moving the hard stuff. Don't suffer!