The magazine listed the measurements, so I took them down and created my own pattern (7.7 cm x 12.3 cm).
I had cut some "nicks" on the top of the pattern, but realized it would be too hard to sew, so I cut my fabric straight across.
I think the Cath Kidson version uses velcro and oilcloth fabric, but I wanted to try making button holes for the first time, so I did just that.