Good old surgeon showing sparkle (7)

I believe the answer is:

glister

'sparkle' is the definition.
(I know that sparkle can be written as glister)

'good old surgeon' is the wordplay.
'good' becomes 'g' (abbreviation).
'old surgeon' becomes 'Lister' (Joseph Lister, father of modern surgery).
'g'+'lister'='GLISTER'

'showing' is the link.

(Another definition for glister that I've seen is " Gristle (anag)".)

I've seen this clue in The Times.

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