I have to admit it's not Portmeirion, yet it is set by the sea.
And if you look at the size of the Village in THEPRIS6NER, it's size is more in line with that of a large Town or even a City. Yet both Villages do have the sea in common, even though it is a very tenuouis connection, seeing as it's discovered to be all in the mind in 'Harmony.' But there is another connection, something of a more substantial nature, that of a Lighthouse, which appears in 'Many Happy Returns' and 'The Girl Who Was Death.' And as it happens, Swakopumnd does have it's very own lighthouse. What's more it's painted red and white!
I think it is a pity that use of this Lighthouse could not have been made in THEPRIS6NER series. I'm not even sure if it can be seen in the background of scenes in the Village. I'll have to check.
Be seeing you