Hi,
You won't get any feedback from NATS if you failed at Stage 1, they state that before you take the tests. If you failed at Stage 2 or 3, give them a call and I'm sure they'll help.
When you reapply, assuming you get through to Stage 1 again you'll get the option of testing dates, so just select a date when you're in the country!
Hope that helps, good luck.