Possible Clues:

• Royal stand-in
• Acting ruler in green dancing tango
• Religious education needed by man who has big shoes to fill?
• Squire gently embracing Queen?
• Extremely rude chap, one with interim authority
• Extremely responsible chap, one standing in for monarch
• Deputy who works to rule
• Interim ruler
• King, say, starts to exhibit neurotic tendencies? I may act for him
• One acting as monarch, for example, in musical