What would you suggest? These are very serious crimes and by pleading not guilty (to two at first which he eventually owned up to, to one which fair enough he was found not guilty of and to another which he was finally found guilty of after a lengthy trial) to them he showed he had little or any remorse.
The fact that the grooming was over a sustained period of time should rightly go against him as well. This wasn't a one-off, it was a calculated lengthy abuse of his position and power to take advantage and sexually abuse a girl who had just turned 15.