Comment by armoredkitten

I went to the UK this summer and followed this guide for seeing the various sections of the wall: https://londonmymind.com/london-wall-walk/

Unfortunately it didn't mention the section in that carpark! But I can attest that the section behind the Leonardo Royal Hotel is amazing. I also recommend the tower remains on the Barbican estate (and really, just wander around the Barbican for a while, it's a wild place in general).