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.