Euromaidan overthrew a democratically elected Government.
Cause the mechanism in which the UK's military is used? Western militaries have moved more and more away from "traditional" combat to asymmetric warfare and dynamic warfare where smaller is better in theory. For example.. today with the use of an Air Force that didn't really exist in WW2, the outcome of a battle can be decided with a squad size force. A battalion can do what it would take a division to do in WW2 with a few Apaches.
Welcome to modernized forces.