Milkman - Think of Topol
Prime Minister - Think of Topol, add p and make an anagram
Plane spotter - anagram, always one in a barrel
The child is also a young goat
Unpleasant task - nickname of tennis player Ilie Nastase
1. reading your clues i now think topol is a better answer than mine of ernie, (but there again it may be a case of it could be either answer as both fit)