I had about heterophorias that if you have one kind of heterophoria out of limits but you don't suffer from double vision and have a good stereoscopic vision (images in relief) you will pass.
I'm afraid that's not accurate. Stereotypic vision is not a requirement for JAA class 1 medicals. Yes, you will get tested for stereopsis but only for the record. Total loss of stereotypic vision won't be a limitation.
Cheers.