Unfortunately I'm no further forward.
As far as I know, this is a real person. Not a concierge (I don't have enough money to stay in hotels like that) and not someone's grandfather.
Because of all the googling I've done, my search history is, as DH puts it, "full of old men".
I have a mental picture of the person, and it seems, I'm just not able to express clearly enough quite how they look. I tried to make a photofit type image but it was horrific, so I abandoned that.
I'll take a look at all the more recent suggestions and update.
All I can add is that it is possible I'm thinking of the character an actor played, rather than the actor looking how I can mentally picture them all the time. However, I'd expect to have seen them, in character, in the searches I've done.
Again, the closest image I have is Richard Griffiths - plump, full head of white hair, quite 'jowly'/double chinned. BUT it isn't him. This person is thinner. They have a longer face than him. They don't have a beard.
Whatever it was they were in, it was filmed in colour. I'm sure it was later than the 70s and 80s. I think the person themselves may be in that age range now, but if I'm visualising them 'in character' then there's a bit of wiggle room.