Clue: Hiding shrunken head slyly, Miss Marple not a saint (5,7)
Answer: SIMON TEMPLAR
Explanation: Definition: a 

***(mis Marple not) **[anag:*slyly*] where MIS is MIS(s) *hiding* S(hrunken) [*head*]
 
*Simon Templar (aka The Saint), created by Leslie Charteris, was played on TV by Roger Moore and Ian Ogilvy.