I'm probably not the best person to ask! Here is some info:
https://welldresseddad.com/2014/03/30/iconic-footwear-paraboot-michael-classic/
The fit is not slim, and has quite a bit of volume in the instep. In a roomy Astorflex boot or Clarks I take a 9, and the 9.5 in these feels similar if not slightly smaller. Bear in mind I have worn them once though so hopefully they can give a bit to allow thicker socks, which I foolishly didn't think about.
https://welldresseddad.com/2014/03/30/iconic-footwear-paraboot-michael-classic/
The fit is not slim, and has quite a bit of volume in the instep. In a roomy Astorflex boot or Clarks I take a 9, and the 9.5 in these feels similar if not slightly smaller. Bear in mind I have worn them once though so hopefully they can give a bit to allow thicker socks, which I foolishly didn't think about.