The cleaners at LHR are atrocious...
We often arrive at the aircraft and find them sat in the cabin chatting, then immediately get up and start doing what they should be when they see us...
They no longer "clean" the aircraft at LHR, it is referred to as a "Cabin Tidy", and they reply on aircraft being cleaned more thoroughly at outstations when they night stop.
Truly a simple basic that is not being done, to the detriment of the brand. People want to travel on presentable and well kept, clean aircraft.