Hi LB,
Duncan chose to not turn up for a rostered flying duty so, whilst I suspect you're broadly correct in your statement of his full-time representative status, he was still expected to fly now and again (if only, one presumes, to maintain recency). Duncan seems to have believed that he could use his union duties to trump his contractual obligation to work - the company disagreed. Thus far, it seems that the appeals procedures have agreed with the company in this respect.
Cheers
MrB