No the engine doesn't need to come out, on a 10 plated traffic master. Not sure about older versions though.
First Step is to drain the gearbox oil.
Disconnect both drive shafts, undo both ball joints, remember to support the weight when reconnecting. Undo all necessary bolts, cables etc. This includes bolts on the starter motor (but do not remove starter motor leave in situ) You will need assistance when removing and fitting, it's fairly heavy. Also remove engine mounts, It will also be necessary to bleed the clutch after re fitting.
Marty, July 2011