Recently my G700 started experiencing the double-click issue; unfortunately it is out of warranty. Searching around on the internet I found a guide on how to fix it here: http://www.instructables.com/id/Repair-mouse-with-double-click-problem/

The mouse in the guide is a different model but the actual switch unit is the same (Omron D2FC-F-7N).  In the process of fixing my G700, I managed to damage one of the mouse feet at the bottom. I bought my replacement feet for the G700 from Cooler Guys. These mouse feet are made by Corepad; they glide much smoother than the original feet and come in sets of 2.