Anyhoo, finally I am happy. It takes a little bit of pull to get it to 12 1/2" but I have done a dummy run and sewn it to other pieces of fabric and it comes out at 12" when sewn all together. PHEW!! Now to unpick it all and send it back to the lovely Kirsty who has organised the RR for us EB Newbie Quilters.
I now feel confident enough to start cutting into other people fabrics! I might wait until tomorrow though when I am not feeling so tired!
So, here it is ... a sneaky peek of my block in my fabric for the round robin.