I've just checked and the minimum on the 19th was 15.6°C. Then I checked as to whether this was a record and, err, surprisingly no. It was nothing that out the ordinary for October.
It was the warmest October since 17.1°C on the 13th in 2018. Last year there was 15.2°C on the 8th October an 15.8°C on the 14th in 2017.
Minimums of 15.0°C is exceeded in most Octobers and occasionaly 16.0°C is as well. I'm surprised by this as my location is not reknowned for its warm nights being a river valley location and inversion boundaries aplenty etc.
1st - 20th
Mean minimum = 9.0°C
Mean maximum = 18.5°C
Mean = 13.8°C
Rain = 42.8 mm