Why would they move it?

York Water Gate it is, trewilliam. I presume that was also Adrian's intended guess but I still wonder why he should have thought they might have moved it. I hope there are no plans to do this as it's an important feature of my guided walk along the Embankment!
Now if you can work out where I went after taking this you'd be on the way to tracking down my other recent gwl entries...

I think this was the first location I guessed correctly on fGWL. It was one of Barbara Rich's photos.

I love that painting of the York Watergate. I have it as the desktop on my computer at work!

Well, firstly you have to bear in mind that there's quite a bend in the river at that point. Secondly, Queen Mary's steps and the York Watergate have steps leading down to the river where people would disembark from boats whereas the watergate at Somerset House was designed so that the King's barge could sail through it. All of Embankment Gardens is land reclaimed from the river when Bazalgette built the Embankment. The Strand is called the Strand because it was initially lined with palaces that all had river frontages (or backs if you regard the Strand as the front...) I have a walk coming up - the River in Chains - all about how Bazalgette's embankment transformed the riverside and clues we can see as to what was there before...