Much as it pains me to say it, some of the 171 fleet has dropped to these levels over the last year or two. They tend to get a decent clean when they head down to the coast, but that’s a rare event (especially for the four car units!). There are travelling and turnaround cleaners but they are generally only equipped for basic litter picking, which is hopeless when you’re dealing with dirty carpet, coffee spills, graffiti or chewing gum.
Cleanliness issues do seem to be a bit of a Govia (not just GTR, but also Southeastern) theme - SE Networkers have long had the problems described, though I have felt there have been some quite recent improvements in the calibre of cleaners and the condition of some fairly surprising areas such as the remaining older-style toilet cubicles. I’ve also found a fair few 700s recently with window etchings, three-day-old Evening Substandards, no handwashing water, vomit and all sorts. FCC 319s were worse but, in FCC’s defence, their cleaning staff had all sorts of unpleasant nooks and crannies to contend with, and they did at least have roving cleaning staff in the London area.