barry, nobody had heard of the Fitzrovia chapel, it was buried in the model of a block mostly occupied by the Middlesex hospital. But they left it standing when the hospital was pulled down (there's now a residential development all around it) and you can visit it on Wednesdays.
The hospital also owned another building over the road, which they have done their best to abandon so it will fall down; squatters have moved in to protect it.
This is the old workhouse, said to have inspired the one in Oliver Twist - Dickens lived just a couple of blocks down the road, and supported the master of the house in his attempts to reform the workhouse system. Readers long supposed the original workhouse was somewhere 40 miles away as it is in the book, but it seems pretty clear this was the one Dickens had in mind.
https://landmarksinlondonhistory.wordpress.com/2017/12/05/the-cleveland-street-workhouse/