HMS Severn passing through Tower Bridge on Friday

A Royal Navy ship, HMS Severn is arriving in London on Friday and passing through Tower Bridge.
What shows up as an unnamed vessel on Tower Bridge’s lift times page will arrive at 5:15pm 6:15pm on Friday 27th August. The vessel will then stay in the Pool of London until it departs at 9:15am on Wednesday 1st September
Now what the vessel is I am unsure of, it’s been confirmed that the visitor is HMS Severn but 99% of the time, when the Tower Bridge’s lifts times page simply says