The axle ratings are just that, ratings. It is the maximum you can apply to that axle. Usually you would have more weight on the rear axle than the front - especially with high ball weights.
You cannot legally exceed the GVM. I don't know the legality of the axle ratings, but if your insurance company can work out you exceeded either of them, they will void your insurance.
The first time I put my first loaded GC over a weighbridge it was 300 kg over weight. I put it on a diet...
Cheers
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