What’s been well done since old radio presenter died (1,4,3)

I believe the answer is:

a good job

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'what's been well done' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'since old radio presenter died' is the wordplay.
'since' becomes 'ago' (I've seen this before).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'radio presenter' becomes 'DJ'.
'died' becomes 'ob'.
'ago'+'o'+'dj'+'ob'='A GOOD JOB'

Can you help me to learn more?

(Another definition for a good job that I've seen is " lucky break?".)

I've seen this clue in The Times.

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