Well made repaint. I was positively surprised at the 122 rollblind, as I've ridden it for years. I haven't seen an ALX400 on the route since 2016 sadly, but as you said, there are a few still left at Catford.
Some are on the 199 and 208, seen this year but most seem to be in Stratford.
I also believe that these ALX400s are one of the oldest stock in London, almost 16 years.