Sounds like pretty normal behaviour from the Merc driver! The thing they often forget is that all the buses have CCTV now so if anything happens then it is quite easy for Lothian Buses to prove who was to blame - amazing how many claims are dropped when this is mentioned!
The Ploverhall junction (like most of the new A701 bus lanes) is pretty stupid as the left lane is the bus lane, but you have to use that one as the right lane is for turning on to the A703! Whoever "designed" it probably never went to the actual location. You would expect with the time it took to complete the project, they could at least get it right! (Ooops, forgot it was the cooncil we were talking about there)