W.A.T.U.
 

It's not often I learn something completely new about WWII history, but the existance of WATU (Western Approaches Tactical Unit) was completely new to me. They wargamed out convoy battles in real-time from reports sent back, both training new convoy escorts commanders and inferring enemy tactics and weapons before making suggestions for countermeasures. This small team, largely composed of mathematically astute your WRENs in there late teens.

https://www.youtube.com/watch?v=fVet82IUAqQ

A very worthy and interesting talk by LindyBeige on youtube

(Edit) I should add that whilst I was previously aware of WATU's training role, it was the conjecture/wargame/devise counter-tactics loop that was completely new to me.