Learnt about flat charge (6)
I believe the answer is:
rental
'flat charge' is the definition.
'rental' can be an answer for 'charge' (the charge for renting something). I am not sure about the 'flat' bit.
'learnt about' is the wordplay.
'about' is an anagram indicator.
'learnt' is an anagram of 'RENTAL'.
Can you help me to learn more?
(Other definitions for rental that I've seen before include "Payment for hire" , "Cost of hire" , "money for landlord" , "Amount paid for hiring something" , "Payment to landlord" .)