However, I do find it easier to concentrate on my designs when the bottle of single malt scotch is out of arms reach

Agreed; however, how often has a "problem" not been due to "concentration". So often when "concentrating" you fail to see another solution that might be better than the one you are "concentrating" on.

Yes, it is valuable to spend time in the Office "concentrating", but do not knock the productive value of time at the pub - or gardenig or whatever.

Erik