Robert Potts, Managing Editor of TLS has admitted there is an error in 18A - the answer to the clue is Celestine, otherwise it doesn't fit with the connecting clues but Stevenson's donkey was definitely called Modestine.
11A - Roger G - confused (but respected) Star Wars commando (6) I have G?E??? (Greene ? - since I'm assuming 3D is 'semantics')
28A - Miss with temperament of Sinclair (7) I have T?R?A?T