This unnamed holidaymaker only appeared in Sea Fever. He was assisting Richard with the luggage.
Hyacinth: Come along Richard, you haven't time for chatting with the porter.
Holidaymaker: Actually madam I am a dentist on holiday. I'm just giving this poor man a hand with all this luggage.
Richard: It was very kind of you.
Holidaymaker: And he appears to have one piece of baggage too many. (leaves)