Could the new Stadler wash plant be the reason units look cleaner? They were positively minging whilst the plant was being rebuilt and then a week or so before lockdown a few looked almost new. I’d presume the new wash plant is much more effective than the old one.
I agree, the units are looking good at the moment.
The end of 2019 was bad. The new wash plant was broken (or not working correctly) and units, externally, were in a bad state. This was especially true for units on the Chester/Ellesmere Port line. With the winter timetable in operation on these lines, some units often go a number of weeks without ever visiting Kirkdale depot for a wash.
I remember 507032 on the Chester line in November and passengers on the platform were astonished by the amount of dirt on the outside of the train. That not helped by the fact people had started to write in the dirt-things such as "clean me".
Thankfully, they are looking much cleaner at the moment.