Is a car "perfectly entitled" to turn left around cyclist
The UK Highwaycode states:


  Using the road: Turning left 
  Rule 182
  
  Use your mirrors and give a left-turn signal well before you turn
  left. Do not overtake just before you turn left and watch out for
  traffic coming up on your left before you make the turn, especially if
  driving a large vehicle. Cyclists, motorcyclists and other road users
  in particular may be hidden from your view


It seems quite clear to me that the driver should not have pulled up to the right of you, which is essentially an overtaking manoeuvre, if he intended to turn left, no matter what you were planning.