Refers to a killstreak in Call of Duty: Modern Warfare 2, where a UAV (unarmed aerial vehicle) would indicate the location of enemies on the minimap. Similarly, cracking the UAV means looking for woman to have sex with.
The phrase "cocking nora" is British slang for "Fucking Hell" as "cocking" is another way to say fucking and "Nora" is used to day hell like in the phrase "bloody nora".