Last one 12/13A "what one needs if going bald on top: energy for one" - Brian. (4,2,3,5) -E-R T- T-E -R-W-. A somewhat more difficult Cyclops than usual!
Brian might be how Private Eye refer to Prince Charles (a guess) they call the Queen Brenda.
hAir to the crown "what one needs if going bald on top"
gets changed (energy for one = E for A) to,
hEir to the crown.