Thanks for the comments - I'll read through these again.
I did find that on the E5-1680-V2 - I could get to 4.3 Ghz for not much more v-core than 4.2 Ghz so I'd say 4.2-4.3 is the place for me - ON AIR !!!! - Really good considering the stock clocks are 3 Ghz
Looking at the gaming benchmarks the E5-1680-V2 did beat the 2700X and wasn't too far behind the 9900K (OK it was a bit behind_but not destroyed by it)_which means it'll be a great CPU and for the price as a used part !!!