I've finally completed the website's care section. At least until significant changes are needed anyhow. The breeding part has been delayed because I didn't feel comfortable writing with no personal experience. But obviously time has wore on and many things have come to light.
I think self fertilisation has now been proven, Gabi posted that one of her immaculata, that was always kept alone laid eggs, which then hatched, Ive also heard of other people keeping immacs seperate at all times from other snails also laying fertile eggs.