Chuck,
It sounds as though will be OK. I have got a Class 1, and I have a slight loss of tone in my right ear at 8000Hz. The loss that you experience seems to be outside the frequencies used for speech etc, so you should be OK. If in doubt, send a copy of your audiogram to the CAA, and they will be able to advise - contrary to previous beliefs, they are really helpful!
For a Class 1, you have an audiogram at initial, then every 5 years to age 40, and every 2 years after that (I think). In the mean time, you have to be able to understand normal conversation at 6 feet with your back to the Doc. You said you passed this for your Class 2, so you should be OK.
Give the CAA a call - if only to put your mind at rest (or even go for the Class 1, but tell them about this. They will then do the audiogram first to check everything is OK)
Hope this helps - good luck!
Barney