e35mkiii

Hello All... I own a 1985 E35 MKIII Tall Rig, hull #211, "Mr Toad". (formerly "Molly May") Can anyone tell me the differences between an E35 vs E35 MKII vs E35 MKIII? I am asked this question often and am starting to get a complex when my response is not much more than a blank stare. Please...