I'm surprised to hear that Tawney was surprised to hear the "dustman affffffft" carried out, since he recorded it that way in 1972.

Interesting. To hear he was "surprised" would certainly be incongruous.

Strictly speaking, the 1972 album came out after Young Tradition's. I would speculate that the way YT was doing it had gained so much force that Tawney actually shifted to doing it in that fashion. I've seen this to be the case a few time that chanteyman Stan Hugill learned songs a certain way, which he presented in his 1961 book, but later on, after singers had twisted the songs differently, he seems to have just gone along with what everybody was doing.

I wouldn't be surprised in Tawney was originally perplexed by the drawn out "aft." Because even when I hear YT's rendition, it sounds "off". Nothing wrong with it in itself (it creates interest), but off from the sailor song style that Tawney presumably was following.