Possible Clues:

• Tepid, like Paula Power?
• Cool chap with the force has battle with militants' leader
• 'And clearest -, amplitude of mind' (Wordsworth)
• Half-hearted physician married in 1946, perhaps?
• Half-hearted biblical writer near to finding the answer
• That saint is not so hot
• Not having high temperature, with doctor fighting onset of malaria
• The French embracing Britain with detachment that's unenthusiastic
• Mark's follower starts close but becomes indifferent
• So-so, as support