That is a lot to spend on a bike to get you back into cycling, given the auction is £820 already.
I can highly recommend the Specialized Tricross Singlecross, I have a 3 year old one that I bought new for £300. It is single speed, but the gear ratio combined with a light but ruggid frame makes ~7% gradients very doable, plus it can take panniers and do moderate off-road.I commute 5 miles on it every workday over an undulating terrain.
I have a Carrera TDF and it is a cracking bike for the cash. Many parts on it are ones that you normally find on bikes much more pricey.
It comes with a standard double crank, but I managed a 48 miler yesterday through the Peak District with around 4500ft of ascent and it managed well. Also managed to get it up to 45mph which was great fun.