The white-painted part you can see in the photo is the counter-weight itself; we were seated about where the photo is taken from, with the performers variously on the steps and in the galleries above.

There was a good warning note on the tickets that the concert times might have to be changed if a ship requested a bridge opening (but they have to give 24 hours notice for that, so by yesterday we knew the concerts would be on schedule).

I was conscious throughout that I was sitting in what is essentially a Bond movie trap, though. Also that I was both underground and underwater.

As I am somewhat claustrophobic, this made some demands, but I was glad to have done it; it was a good experience.