Thanks everyone for your responses so far.. I've actually just now tried this combination on the workstand and to be honest it seems to be working fine, haven't had it on the road yet but I have no reason to think it won't work now. Obviously I'll try it out on the road quite a bit before I head to the Alps
The gears are shifting just as well as they did on the 11-28 set up... only thing I may do for extra piece of mind (as someone pointed out) is lengthen the chain slightly, as when its in the big big combo it does look a tad stretched out. I have no plans to ever ride in the big big but hey you never know I guess and really don't want to take any chances whilst I'm out there!