I used to own an Arcam A-28 and an Accuphase rig (A-45 amp and C-2410 pre) at the same time. I have used the Arcam (together with a set of Dynaudio Audience monitors and a Rel Quake subwoofer) in the living room for TV watching, while the Accuphase system was used in my music room.
The A-28 is certainly a nice (life-style orientated) integrated amp, but it is nowhere near the level of any Accuphase integrated, e.g. E-308/408, E-350/450/550, E-460/E-560, etc.. Accuphase is really a hi-end manufacture and this is reflected not only in sound but also in price, i.e. the E-460 will probably be significantly more expensive that the A-49 (at least a factor of 2 if we consider retail prices). I am sure the A-49 will be significantly better than the A-28, but I doubt it will be as good as the Accuphase. The Accuphase will probably not be twice as good, but for sure will make you twice as proud an owner.
Finally, I do not have experience with Arcam and B&W, but Accuphase and B&W speakers from the 800 series is a very very good combination.
Good luck and keep us posted!