Tax relief on travel expenses from home to a port re employment on a ship

I have a client who works on ships for an overseas employer but does not spend enough time out of UK waters to be entitled to SED. The client worked on the same vessel for all but one of his trips in the year in question but boarded at different ports in both Scotland and overseas. When he travels to and from overseas ports, his employers cover the cost of travel to and from the port. However, when he travels to and from UK ports, he must cover his own travel costs from home to the port and back.

I would like to know whether he is entitled to tax relief on his UK travel expenses using the Temporary Workplace Rules although I am unsure whether the port or vessel should be classed as his workplace. (I know rig workers are allowed to claim if they transfer between rigs in different oilfields and wonder whether a similar principle could be applied in this case).