Hi Chris, i got 1 size up, im normally a size 8 but got size 9, they are big sized anyway. With one size up i am able to wear 2 pairs of smart wool winter socks which are thick in size and ive still got plenty of wiggle room.
The bottom area betwwen the sole of the boot and the laces section is rubber and very flexible, so they dont feel tight like normal leather boots...
Hope this helps, and good luck with the bank manager, if you are like me you might have to think of a visit to him for this exped, it soon racks up the costs doesnt it.....
Col.....