Maybe a reminded of the offence that occured :
With regards to the sentencing guidelines, I would suggest :
No significant planning
Possibly acted with another - the other guy mentioned had the exact same offences?
No alcohol or drugs used
No abuse of trust
No commercial exploitation
Possibly no disability involved
No weapon involved, no nudity
With regards to the victim being 14, the only mention in the sentencing guidelines regarding age relates to grooming for a person under 18. I suspect most normal people wouldn't consider a slap on the arse to be 'grooming'.
Then there are the mitigating factors that we don't know about from the snippet, but that the judge would have taken into consideration...