This did for the holiday but because I'd had to fold up so much fabric it was starting to leave marks (see photo below).
So when I got back from New York I put the jeans back in my drawer to do at a later date. Well I decided to bite the bullet this Spring and got them back out. You can see just how much fabric I had to chop off below (the weird marks on the photo are greasy prints on my camera lens - sorry!).
So I looked at a few YouTube tutorials but they all seemed a bit complicated as they started giving measurements and instructions on how to re-hem using the original hem - all seemed a bit too much for me!
What I did take from them though was the advice to zig-zag or overlock the cut off edge so it doesn't fray. I chose to do a zig-zag stitch on this. Then I measure the jeans on me, pinned them, checked they were both even, and cut into the jeans. I found thread that was as near a match as could be, after asking for help in John Lewis about the right kind of thread to use on jeans. I did a straight stitch, very small, and I think it looks like a pretty good match. I wore them out on Thursday night and they haven't come undone or frayed yet so I'm pretty happy - new jeans for the summer yay!