Possible Clues:

• Temporary ruler
• Young stand-in priest, purged of sin, insincere fellow
• George IV, perhaps, runs in furiously preening, etc
• Future monarch's charge concerning chap touring north
• Priest in church torn about, say, royal stand-in
• A stand-in for royal pair, genuine chap hasn't succeeded
• The future George IV in 1811-20
• George III's son was one such
• As George IV was during eighteen eleven - eighteen twenty
• George IV, before he became King