Made up again by popular outlet with a fair amount of grass on either side (10)
I believe the answer is:
Here is my best explanation:
'made up again' is the definition.
('invented' can be a synonym for 'made up' so perhaps 'reinvented' is OK for 'made up again')
'grass on either side' is the subsidiary indication.
'grass' becomes 'reed' (I've seen this before).
'on' indicates putting letters inside.
'either side' becomes 'invent' (I can't explain this - if you can you should give a lot more credence to this answer).
'reed' enclosing 'invent' is 'reinvented'.
'by popular outlet with a fair amount of' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Another definition for reinvented that I've seen is "Thought up again".)