(20 Oct 2015, 9:43 am)Dan wrote The "NOT IN SERVICE" display isn't a 'full screen' due to the fact this vehicle has a colour panel. If it was left in the colour panel, it would look something like this:
Go North East: 4938 / NK51OKX by Daniel Graham, on Flickr
If you mean something else, and there is a genuine fault (which you probably do, given you said the right hand side was working and not the left), we'll have a look at it next Saturday. It could be something as simple as a wrong switch setting - I know the back of the Mercedes Citaros are set up as the back of an OmniCity (which is a completely different size), so that's why they look a little strange.
The rear screen was only showing 'OT IN SER' when it was dumped in Durham when I passed through at 0950.