N2P:
Your left eye correction is 2.00 dioptres (the spherical component alone) along the 22.5° axis and 2.00 + -3.25 = -1.25 dioptres (spherical plus cylindrical component) along the perpendicular (112.5°) axis. So the worst error for this eye is 2.00 dioptres. (That is the "deviation from emmetropia in the most ametropic meridian" referred to in JAR-FCL 3 3.220(b).)
Your right eye correction is -1.25 dioptres along the 180° axis and -1.25 + -0.50 = -1.75 dioptres along the perpendicular (90°) axis. So the worst error for this eye is -1.75 dioptres.
Your degree of anisometropia is the difference between the two worst cases - i.e., 2.00 - -1.75 = 3.75 dioptres.
I should point out that I am not an optometrist so I may be completely wrong on this. But this is what I believe the numbers mean. Sorry it's bad news for you. (If it's any consolation, I can't even get a Class 2 due to my short sight being beyond the limits. Looks like I'll stay a wannabe until they relax the limits a bit more...)