Store has brown jumper in large and medium (6,4)
I believe the answer is:
lumber room
'store has brown' is the definition.
'lumber room' can be an answer for 'store' (I've seen this before). I'm not certain of the 'has brown' bit.
'jumper in large and medium' is the wordplay.
'jumper' becomes 'roo' (short for kangaroo, something which jumps).
'in' is an insertion indicator.
'large' becomes 'lumber' (I can't justify this - if you can you should believe this answer much more).
'and' means one lot of letters go next to another.
'medium' becomes 'm' (as in UK clothing sizes).
'lumber'+'m'='lumberm'
'roo' inserted inside 'lumberm' is 'LUMBER-ROOM'.
Can you help me to learn more?
(Another definition for lumber room that I've seen is " store".)