Yes, so Meic Stevens, finally.
Meic's autobiography says that in the sixties he wrote a song in English about his uncle Walter who went off to war on the submarine Tarpon (appears as Tarpan in the song). It was sunk in the Baltic campaign in 1940 and Walter never came back to Solva.
When Meic began to wonder about singing in Welsh, he just knew a few folk songs but they went down very well on the radio and TV so he thought about writing his own material. He took Walter's song to a teacher he knew and they put together "Can (circumflex over the a) Walter."
There's a nice version with a female harmony vocal by Heather Jones and organ and guitar accompaniment but Meic's own solo version with guitar is probably better. Less is more, as they say.
Meic is bringing out another English record later this year and this is going to be on it. The title is, "Bound for the Baltic Sea".
Of course, my fear is that if I learn this Welsh song, Welsh people will say, "Oh, for goodness sake, not "Can Walter" again !" A bit like English people think about "Streets of London"
Having said that, though, try looking for the lyrics in Welsh on the internet. You'll look for a long time and still not turn up very much so perhaps it isn't done to death just yet.