Too much choice need help

[43383055]

Im looking to buy a bike for the short commute to work. Main problem is my low budget and the commute has 1 very long steep hill in it which I have to get off and walk some of it with my current cheap heavy mountain bike (weighs about 15kg)

OK must have for the Bike:
Disc brakes hydraulic if possible (the road is very busy and as I said steep so go very fast down it to work and I like the stoppig power of these brakes)
Flat bar (cant get used to drops)
As Light as possible
Not Twist shift gears
Large size im about 5-11 to 6ft
&700c wheels/tyres

Would like:
£400 to spend ish may go higher for a brand new bike but I am looking at used ones as well
pannier rack would be nice or at least holes to attatch one
Mud guards

There just seems to be so many that nearly fit what I want but none dead on for example:
http://www.evanscycles.com/products/pinnacle/lithium-three-hybrid-bike-ec027463 pinnavle lithium 3
also some of the boardman hybrids

Specialized Sirrus looks nice but is missing the disc brakes.

Any one with any ideas?

 

[Nufab]

Have you ridden a bike with hydraulic disc brakes before? I ask because I have ridden several, and they are nice. However, I've got rim brakes on my MTB, and I can easily lock up the wheels with them... Therefore I can't stop any quicker!

If I were you, I'd test ride a few bikes, and see if you think you really need the discs. Hydraulic discs are a pretty expensive component really, and at that budget I'd think you could use the money on other things.