Telegraph 's lead editor, admitting awful blunder, is one wheeled out for retirement? (7,3)

'one wheeled out for retirement?' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.

'telegraph 's lead editor admitting awful blunder' is the wordplay.
'telegraph 's' becomes 't' (I am not sure about this - if you are sure you should believe this answer much more).
'lead' is a charade indicator (letters next to each other).
'editor' becomes 'ed' (abbreviation).
'admitting' means one lot of letters goes inside another (admit can mean to welcome in or accept).
'awful' indicates an anagram.
't'+'ed'='ted'
'blunder' is an anagram of 'rundleb'.
'ted' enclosing 'rundleb' is 'TRUNDLE-BED'.

'is' is the link.

Can you help me to learn more?