Sian: "And there's a bit of a problem, to my ear, with "On the seashore" as there would be too much emphasis on the "the". "Beside the sea" works better in that sense, except for the echo of "By the sea, by the sea by the beautiful sea!" "

"Along the shore" might do it, and keep the rhyme and scansion. Any other rhyming is a little dubious as so much of it rhymes ****ion with ****ion. This is the equivalent of rhyming ***ing with ***ing, and should make things simpler except for the need to translate 5 syllables as 5 syllables (If keeping the feel of the repetative first half line). That would add a greater degree of difficulty to the attempt. I'll see how it goes, so this might be my only comment on the matter

Nigel