Writing on ruin of new coach (4-2-4)

I believe the answer is:

four-in-hand

'coach' is the definition.
('four-in-hand' can be a synonym of 'coach')

'writing on ruin of new' is the wordplay.
'writing' becomes 'hand' (hand is a kind of writing**).
'on' says to put letters next to each other.
'new' indicates anagramming the letters.
'ruin'+'of'='ruinof'
'ruinof' anagrammed gives 'fourin'.
'hand' after 'fourin' is 'FOUR-IN-HAND'.

I've seen this clue in The Telegraph.

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