There was some discussion a while ago about ads on the back of buses.
EBC used to use this one.
This one is used in Manchester as part of the Love Your Bike campaign
LYB is surveying people about "Buses and Bikes Sharing Road Space"
"This survey is being carried out to help get a better understanding of the perceptions and experiences of people who cycle in Greater Manchester and share the roads with buses"
Maybe CCE Forum/Spokes should run something similar. It's often said on here (with justification) that Lothian Bus drivers are generally considerate. Quantifying this and comparing with a city elsewhere might be instructive.