Passion fruit?

Up to the house this morning for a new electric meter to be fitted.  While I was waiting for the engineer, I had a wander up to the top of the garden and noticed these growing on the tree overhanging the back of the garden.  My friends on Facebook were almost unanimous in saying they were passion fruit (apart from one who thought they were rosehips.  Um, no.).  However, none of them could say for sure if they were edible or not.  I pulled one of the tree, and it came of easily and had seeds that looked a little like pomegranate seeds inside.  

Obviously, I'm not to going to eat them until I know for sure, but if anyone has further information, it will be gratefully received!