www.mr-shoes.co.uk/womens/G/boots/C/MnP/MxP/CO/marco-tozzi/25615-women--s-buckle-high-boot-black.aspx
Although I only paid £55 at Pavers for them.
I have 42 inch calfs and I can get these zipped up - and with a pair of treggings too. (A bit tight - but they do go all the way up!)