"It,s hard to think of Wapping and the Isle Of Dogs as romantic placenames."

No it's not - it all depends what happens to you there. I think that's part of what Ewan is getting at - in the context of a romance, all places become romantic. Anyway you get great sunsets from the Isle of Dogs sometimes.

I can never hear the line "springs a girl in the streets at night" without getting a vision of some Jill the Ripper character.

One thing about the old gasworks - they realy were smelly places, and the whole area around reeked of them. That wouldn't have needed pointing out at the time, but nowadays people don't have that association, because the gas pumped in from the North Sea doesn't have the smell.

I've got the feeling the song is a bit earlier than 1968. I'm sure I remember Ewan singing it in the Ballads and Blues Club in Soho Square in the late 50s.