I had loads of leathers off flea bay in the past and found that the sizes vary greatly from make to make!!! so in the end I went to a shop and tried them on and purchased there.
Regarding fit, they should be pretty tight so the armour dont move about in the event of a spill, dont forget that they are shaped to fit better in the riding position so thats why they can look a bit funny when you see people walking about in them.
I got a matching 2 piece which looks like a one piece when fastened up, much more practical for taking a piss or cooling down if the weathers nice when you stop for a pint at Matlock !!!!

Try J&S to see if there is one local to you.
I got a set of Akito Imola in the shop for £120, should have been £250 !!!! Pic below.
http://images.google.co.uk/imgres?imgur ... N%26um%3D1
J&S website
https://www.jsaccessories.co.uk/
Jim.