Point discolorations out on the map of Surrey (7)
I believe the answer is:
staines
'the map of surrey' is the definition.
I can't tell whether this defines the answer.
'point discolorations out' is the wordplay.
'point' becomes 'E' (compass point).
'discolorations' becomes 'stains' ('stain' can be a synonym of 'discoloration').
'out' indicates putting letters inside.
'e' going into 'stains' is 'STAINES'.
'on' acts as a link.
Can you help me to learn more?
(Other definitions for staines that I've seen before include "Town SW of Heathrow" , "Surrey town on Thames" .)