If you are limited to Evans, and limited to £800, then looking at a sorted list on their website, the best frame available for your budget is the 2014 Cannondale CAAD8 Sora. Shimano have upgraded Sora this year (so no side buttons) and it is good kit. This is an outstanding frame with a beginner-friendly longer headtube. You will need a 56cm. After breaking my own bike (Giant TCR), I’ve raced an upgraded# CAAD8 for the past two weeks and it is genuinely wonderful. The second best alloy frame (after the CAAD10). The only downside has been that the BB30 bottom bracket needed regreasing, a £12 job at my LBS.
At the price you are looking, no bike will have good wheels or tyres, I’m afraid. You can lose almost a kilo with an upgrade for about £350 and transform the bike. But the CAAD8 is a superb introduction to road biking and better than cheap carbon frames costing more.
If you aren’t limited to Evans (who don’t stock Giant), the Giant Defy has better wheels at the price and a compact frame if that appeals. Neither will be found wanting
#Ultegra shifters and brakes, Ritchey monocoque carbon forks, stem and bars. Carbon saddle.