Am i missing something or have you got more than 3 highers at grade c or above?
I think you have so where is the problem?
If it says C or above then thats what you need.
NATS isn't a university so i doubt they would discriminate for someone with better grades.
When I applied I had sat my A levels but was waiting for the results. I got the results whilst at the college and had got an N and 3 U's.
13 years later I'm approaching the top of the scale. Intelligence doesn't equate to ATC ability.
Thankfully!