That Rose looks like a lot of bike for the money !
I think that discs are good for most types of riding if it's wet or muddy but then I would say that
As Smurphboy says the Boardman is an alternative and there are several people on Cycle Chat who have them and are very happy. It does, however, look like quite a heavy bike to me and that's before you've put a rack and dyno hub on it.
I imagine that, for audax you'd need to change the tyres on both the Boardman and the Whyte whereas the Marathon Supremes on the Rose are great for road riding (they're probably my favourite tyre).
A friend of mine has just had the LBS build him a Kinesis Tripster ( http://www.kinesisdecade.co.uk/product.php?id=1
) and, so far he's very happy with it. The frame and fork arrived as a package and then he specced the rest of it. Doing this would mean that you could use some of the bits that you've already bought.
A leftfield option would be the Planet X Dirty Disco but you'd have to be creative with the guard and rack mounts.
What Kinesis fork did you get and, purely acedemically, would you be selling it if you go for a complete new bike ?