I thought the FAA ATP flight test included the IR? I think you can only get Private priveledges based on the JAA ATPL. Would need to do the CPL/IR unless you have the 1500 hours required for the ATP. Written tests can be done in the UK at one or two testing centres, much cheaper to do the flying in the States though, as I learned to my cost. If I had the money to do it again I would probably chose the best school in the States, 'FlightSafety Academy' (in my opinion of course!)