This is all very true. In my case, the minimal requirement was a range of 107 km in even the worst conditions. That means I should still be able to make my daily commute without having to charge, even at the end of my lease.Driving patterns and terrain have a considerable impact on range just as much as ambient temperature does. If you have the misfortune to need to stop at numerous intersections this will cost you range. If you need to drive over hilly terrain this will also cost you range. Likewise, turning on the heater will cost you range as will driving at speeds where wind drag becomes a significant factor.
Truth is that actual range can only ever be accurately predicted once it has been established. If you've never driven from point A to point B before, and if the number of stops or the terrain is unknown then it's impossible accurately say whether or not point B is within range unless point B is dramatically within the limits of the predicted range that there is little risk of any problem. The tough drive is the first one - when you're trying to determine whether or not point B is within range. Once you've made that drive you can then reproduce that drive very predictably under similar conditions.
It's why having a range extender on an EV with a short (<100 mi) all-electric range is so attractive and pragmatic at the present. You don't experience anxiety over whether or not point B is within range. When the public charging infrastructure (and especially destination charging - imagine if the OP had been able to charge while parked on the street in Guildford) is more prolific then range anxiety is much-less pronounced.
So, starting from a modest range of 150 km with a new car in perfect weather, I reckon 10% capacity loss, giving a range of 135km after 4 years. Then allowing for 20% reduction in a cold winter, I would still get 108 km. Pushing it like that would not be nice every day, but our winters don't normally last that long...
But the OP is getting this king of range with a new car and not even in really cold weather. That's what surprised me, although it can probably be explained by hills and other factors...