Change the police force's core mode of transport (10)
I believe the answer is:
helicopter
'mode of transport' is the definition.
'helicopter' can be an answer for 'transport' (helicopter is a kind of transport). I am not sure about the 'mode of' bit.
'change the police force's core' is the wordplay.
'change' is an anagram indicator.
'core' means to look at the middle letters.
The middle letter of 'force' is 'r'.
'the'+'police'='thepolice'
'thepolice' with letters rearranged gives 'helicopte'.
'helicopte'+'r'='HELICOPTER'
Can you help me to learn more?
(Other definitions for helicopter that I've seen before include "aircraft" , "Flier" , "Chinook" , "surveillance equipment" , "surveillance vehicle" .)