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 this works.
'prepare for taking mum' is the wordplay.
'prepare' becomes 'make' (synonyms).
'for' says to put letters next to each other.
'taking mum' becomes 'way' (I can't justify this - if you can you should give a lot more credence to this answer).
'make'+'way'='MAKE WAY'
'to' is the 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)'" .)