I don't have any knowledge of what a "reasonable" homicide rate is, but that seems extraordinarily low for anywhere in any point in history.
If London had the same homocide rate per capita as Seattle, that would equate to 1459 homocides in the same period.
[1] https://www.macrotrends.net/cities/22860/london/population#:....
[2] https://www.statista.com/statistics/862984/murders-in-london....
I don't have any knowledge of what a "reasonable" homicide rate is, but that seems extraordinarily low for anywhere in any point in history.