On a number of occasions I sympathised with Servicemen over this. I recall one senior Army officer moaning to anyone who'd listen that it was so much easier getting to Colchester from London for a hearing, but a bitch now we'd moved to AbbeyWood. That, the "bastard" was guilty no matter what the evidence, simply because of the inconvenience. He was found guilty. To be fair, that senior officer was loathed but his ethos was adopted by his juniors in order to progress.
The CS system is so much easier. A senior grade simply rules that the issue does not constitute grounds for grievance, so there can be no grievance. (e.g. CDP Walmsley - a retired Admiral, which may be significant - when ruling fraud is not an offence, therefore one could not raise a grievance when disciplined for refusing to commit fraud). If you do pursue it, the "offender" is permitted to judge his own case. Exceptions are rare.