Change at Heathrow? (5)
I believe the answer is:
pence
'change at heathrow' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pence that I've seen before include "Small sum of money" , "''Take care of the ..... and the pounds will take care of themselves''" , "Small coppers" , "Fractions of a pound" , "They were hundredths of a pound" .)