1820: KG3 died 29th January. He had not been lucid since 1810.
There were uprisings and plots throughout the U.K. -
Feb - Cato Street Conspiracy in London, five conspirators were hanged and beheaded on 01st May.
March & April - rebellions in Scotland - three hanged & beheaded (last beheadings in Britain)
- and rebellions in Yorkshire.
So, I agree that 1820 was a "hot" year, in political terms, but I can't see the connection with this Hobo-Art.