In the red van, order forms filled in by head of warehouse (9)
I believe the answer is:
overdrawn
'in the red' is the definition.
(I've seen this before)
'van order forms filled in by head of warehouse' is the wordplay.
I cannot really see how this works, but
'order' could be 'ove' and 'ove' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for overdrawn that I've seen before include "The big spender's account may be so" , "Cartoonishly exaggerated" , "bust?" , "is no longer credited" , "venturing into red" .)