Addressed upper houses in one's glad rags (7,2)

I believe the answer is:

dressed up

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'one's glad rags' is the definition.
I can't tell whether this definition defines the answer.

'addressed upper houses in' is the wordplay.
'in' says the answer is hidden in the clue.
'DRESSED-UP' is hidden within 'addressed upper houses'.

Can you help me to learn more?

(Other definitions for dressed up that I've seen before include "Put on uniform" , "All misleadingly presented" , "Well turned out" , "Disguised" , "smart" .)

I've seen this clue in the Sydney Morning Herald.

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