Flower arranging stock reduced in store (7)
I believe the answer is:
'flower arranging' is the definition.
(Japanese method of flower arranging)
'reduced in store' is the wordplay.
'reduced' becomes 'ban' (I can't explain this - if you can you should believe this answer much more).
'in' is an insertion indicator.
'store' becomes 'IKEA' (furniture shop).
'ban' going into 'ikea' is 'IKEBANA'.
'stock' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ikebana that I've seen before include "Japanese art of flower arranging" , "Japanese flower-arranging art" , "Art of Japanese flower arrangement" , "Flower arranging; In a bake (anag.)" , "arrangement of flowers" .)