When did England stop cutting poachers' fingers off and just give them a fine?

I think it was about the time people got proactive about what goes into pink slime.

Read this article from Wikipedia here

Apparently starting around 1810, the punishments were reduced. See the last paragraph

It is amazing how much things changed during the Enlightenment, which started in the 18th century. Before the Enlightenment people were drawn and quartered, burnt at the stake for witchcraft, and thrown into debtors prisons. There were a whole bunch of crimes treated as capital offenses, torture and maiming (as you point out) of prisoners, and nobody had any qualms about slavery. I highly recommend Steven Pinker’s book, The Better Angels of Our Nature, which discusses at length the decline in violence since the Enlightenment.