That's a very good and nice account of the different seasons.
I would say it's pretty accurate for southern England.
I live in central England and have also spent some time in the north.
In the most northerly part of England (which is on the same latitude as southern Scotland), the sun sets at around 23:00-23:30 in the height of summer (I'm thinking early July here ^^). I'm not sure of the exact sunset times though - I guess I could look them up. *lazy*
I have been driving along at midnight and still been able to see the light of the sun where it's sitting juuuuuuust below the horizon, in the very north of England. I love those long summer nights!
In mid-October - now-ish! - I would say sunset where I am is around 18:30. I haven't checked exactly, and of course it seems to get darker more quickly when there is cloud cover and/or in a built-up area. Yesterday, for example, it appeared to my eyes fully dark at 18:10 (although I'm sure that out in the open country it would have been only almost sunset).
October is one of my favourite months, and although it is getting colder, the weather isn't always rainy or horrible. I love the days when it's cold and even frosty, but lovely and clear, the air cold and sharp and a gorgeous light on the coloured leaves. This is particularly nice in early morning and just before sunset. There are even days like this in November despite its reputation for being foggy and gloomy.
In December, street lights and car lights are often on as early as 15:30 (or before, if there is a lot of cloud), and it's completely dark by 16:30. (Once again, though, I don't know the 'official' sunset/sunrise times )