Motorcyle courier's free half of beer (5)

I believe the answer is:

rider

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'motorcyle courier's' is the definition.
I can't tell whether this definition defines the answer.

'free half of beer' is the wordplay.
'free' becomes 'rid' (to be free of something is to be rid of it).
'half of' suggests halving the letters.
'beer' cut in half is 'er'.
'rid'+'er'='RIDER'

Can you help me to learn more?

(Other definitions for rider that I've seen before include "Equestrian or biker?" , "One who's got up" , "Addition to verdict" , "knight" , "Revere, for example" .)

I've seen this clue in the Evening Standard.

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