For what it is worth I will say the ATPL ground school staff at NAC are a lot quicker and more likely to respond to emails than the flight school department.
As Nikki says the Instructors have nothing to do with the Admin side of things. From a laymans point of view, the closest that the instructors get to the Admin side is arranging flight schedules (which is run on quite a good system - nothing like their email systems!!!).
I have come away on two occassions with first time passes in FAA CPL, IR, Multi checkrides all within the allocated time with some to spare... and I know of others personally who have done the same.
As for hour building? Not really done any "fun" flying whilst at NAC. Except the odd one or two trips up to Lakeland and Venice.
I know this is a thread about NAC but for hour building I'd go to California... more variety in scenery, mountains, etc... Landing at Santa Barbara on the Pacific coast in the morning, lunch at Big Bear at 6500' MSL in the mountains and another hour and a half flight you'll be in at the big city within the desert... Las Vegas for the evenings entertainment!
ChocksAwayUK,
As you're only going to be hour building (according to this thread) then you will not require a visa. You can enter the USA on a visa waiver scheme.
I believe there may be a TSA requirement once you get to the USA though - I may be wrong though and I'm sure Nikki has informed you of what is required.