Thank you very much everyone for all the suggestions
I have wondered about fraying it but am a bit worried as it will obviously need washing from time to time. Yes, an edging stitch might help with that
I have thought about machine stitching but I have a tendency to let the machine run away with me and is not as neat as it might be. Will try slowing down.
I like the idea about the lining coming round to the front to form an edging - not done that before.
Yes I have got Easing into Hardanger and wondered about the four sided stitch - has anyone tried it on aida ?
I think I am going to have to try a few of these on some spare fabric.