She has replied, I'm pretty happy now, thought it sounds like I'll be paying for the return postage!
The rise does look high in the picture. The crotch width on the medium is a bit wider than on the M/L size (feedback, way back when, was the the medium size was still used a lot of exclusively breastfed babies and having the wider crotch width on that size was better to keep in messy messes). But the rise is about 2" different; it does look high in the picture though. You can send it back and I can make up another in the medium but trimmer, and maybe shave a little bit off the rise? What do you think?