As a driver if you're given an instruction by the signaller not to call somewhere, you follow it. That wouldn't be classed as a fail to call, unless there was something more going on.
Classed as a fail to call because driver suggested it without authority of his control. Signaller agreed to it and claimed he'd thought the Driver had authority of TOC. Driver then took it. Management also tried to do him for taking a wrong route but this was dropped.