Hi,
I wouldn't get too hung up on the standmounter vs floorstander debate. You just need to get the best speakers for your system/room/budget.
In your case I think the KEF iQ5SEs would work the best. They're less obtrusive and cheaper than the B&Ws (once the 685s are on stands), and would be a better match with your Arcam amp. Take a listen to the KEFs. I doubt you'll be disappointed.