Prepare for taking mum to Kew some day (4,3)
I believe the answer is:
make way
'kew some day' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'prepare for taking mum' is the wordplay.
'prepare' becomes 'make' (synonyms).
'for' is a charade indicator (letters next to each other).
'taking mum' becomes 'way' (I am not sure about this - if you are sure you should believe this answer much more).
'make'+'way'='MAKE WAY'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for make way that I've seen before include "What road builders do" , "Stand back!" , "Allow room (for something else)" , "Clear a path" , "'Allow room for someone else (4,3)'" .)