I am more likely to believe Gasp0de's theory. The following week Marcus made some off the cuff remark about nothing untoward happening, I don't remember his exact words, but it chimes with something being very wrong the week before.
That seems more likely than Stena having a signature dish - unless they have a posh dining option on some of their longer ferries? There is hardly time to do anything but get a drink on the channel ferries.