Firstly thank you to everyone that took the time (and effort) to offer advice on the various bikes available and the options on those bikes.
Never realised how in depth you can get with buying a bike!
Anyway, i have now chosen a bike.....A Kuota Korsa Lite.
I can spec different bits on the bike, and one of those options is the gears (sorry if i'm describing this all wrong!, I haven't tagged myself the virgin racer for nothing!).
The bike comes with Sram Apex, which i can upgrade to Shimano 105 or Sram Rival.
The additional cost would £100.
Any advice would be greatly appreciated.
Groupset!! Its called the groupset, that's what i can upgrade!