Go in to Motomail & try on a selection of boots & order the average size. 
I found that I went from a 42 to a 44 when Alpinestar did a major change in the style of their road race boots. You really need to try them on or arrange to send them back for replacement if they're too big/small.
Personally, I wouldn't buy something like that over the internet without being able to try them on first.
Good luck.
"Women & cats will do as they please, and men and dogs should relax and get used to the idea." Robert A. Heinlein
"Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." Bruce Graham
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