Contacted Lothian Buses (or 'Exterion Media', the company who deals with Lothian's advertising) earlier to get some rough prices on advertising on buses, and received a reply within 20 minutes from the Business Director of the company who forwarded my e-mail on to another employee who can assist.

As I explained that I requested these details to help with a Business Studies assignment I have, I'm incredibly shocked (and chuffed) that I received a personal reply in such a short period of time.