I decided to make this pinafore/dress.
When sewing jumpers I find it better to do a straight stitch and then neaten and seal the seams with a zig-zag stitch. Overlocking tends to put the pieces out of shape. Pressing and steaming is also important.
I had to "make do" a bit on the back panel because of the damage to the original jumper so it has three panels.
I have just started a recycled jumper/sweater pinterest board - so far mostly sister outlaws things but I hope to add more recycling inspiration there.