Bastard offspring stealing a gallantry medal (2-3-2)

I believe the answer is:

so-and-so

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'bastard' is the definition.
(synonyms)

'offspring stealing a gallantry medal' is the wordplay.
'offspring' becomes 'son' (male offspring).
'stealing' means one lot of letters goes inside another.
'gallantry medal' becomes 'dso' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'son' going around 'a' is 'soan'.
'soan'+'dso'='SO-AND-SO'

Can you help me to learn more?

(Other definitions for so-and-so that I've seen before include "Right little rascal!" , "Difficult person - nobody in particular" , "Disliked person" , "Someone or other - unpleasant person!" , "Unnamed person" .)

I've seen this clue in The Independent.

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