(06 Sep 2017, 7:50 am)Jimmi wrote Problem with that is half the time they do all that whilst driving between Gateshead Interchange and Newcastle from my experiences, good luck trying that on the 21 as it doesn't get that long at Eldon Square (and that's if it's on time of course  )

The blinds and machines traditionally were always done when waiting at the lights at the bottom of High Street West, when heading to Newcastle.
My awareness of interworking came about courtesy of those lights, whilst just a youngster.
Whether it's still done now, not sure. The effort to change a display is a lot more subtle and discreet, compared to the old roller blinds.

However, I think the operators need to overcome obstacles like the ones you mention, in order to keep their vehicles clean and presentable. The cleaning could be carried out at the other end, or even Chester.
Maybe, we see a Pavlov's dogs type effect where a clean bus leads to a re-condition of how passengers behave.
A clean bus may disuade passengers from making a mess. Opposed to passengers thinking that making an additional mess, wont make much difference to the mess already made.