NASA has made a rather weird video of the tides from a global perspective, based on data from satellites. The fact that the UK is squashed into the top right hand corner is frustrating!
With grateful thanks to Sue Atkinson here is an impression of the bell to be installed to the West of the Rotunda (itself hiding a sewage pumping station). It isn't installed yet - it just looks like it..... Here's the view in the other direction (taken on a sunnier day).