The Croydon area seems to have been very badly hit.
...
The weather in the afternoon was much worse than it had been in the
morning

Although we seem to have had five or six inches of snow build up over the
day, rather that the possible 1-2cm that was being forecast on Monday
evening, I wouldn't say the Croydon area has been particularly badly hit
weather wise. It has just snowed. It is not like a couple of years ago
when we woke up to nearly a foot of the stuff. The pavements which had a
lovely layer of fresh snow this morning have got a little more treacherous
in the afternoon as the snow has been trodden down but the roads don't seem
so much worse than they were first thing.

The trouble with Croydon is that it takes very little to gum up the works.
The main roads are very busy at peak periods at the best of times, and a
single closure or diversion on a major road can have a knock on effect a
couple miles away (e.g. the closure of Coombe Road for a few days a while
back was clearly reflected in the level and speed of traffic on the Lower
Addiscombe Road). So even the most modest amount of snow has a major effect.
Once the roads are bunged up the bus network, which is pretty good normally,
is of course stuffed. Similarly there is an impressive rail service in
Croydon when all is going smoothly, but it is at capacity and it takes very
little to reduce it to chaos.