"n fact, 'Thames' and 'Collier' are extremely close - I've never really noticed how close before now"
yes, but because I suggested they were the same, which they are, I was not sniping at MacColl, they are both good songs, although the alleged Bert composition is in my opinion marginally better.
I was trying to ascertain, which was first, because it might have thrown light on the lack of traditional authencity of the bert song if sweet thames had been written first, please stop being so defensive and childish, Jim, you have lots of useful information which you can impart without jumping to wrong concluisons, and name calling.
so it seems MacColl fitted words to tunes when he wrote songs, which may be useful info for aspiring songwriters, this was apparently what MacCartney did for the beautiful song Yesterday.