Rally blames organisation around the London area (8)
I believe the answer is:
assemble
'rally' is the definition.
(I've seen this in another clue)
'blames organisation around the london area' is the wordplay.
'organisation' is an anagram indicator.
'around' is an insertion indicator.
'the london area' becomes 'SE' (South East postcode).
'blames' with letters rearranged gives 'asmble'.
'asmble' going around 'se' is 'ASSEMBLE'.
(Other definitions for assemble that I've seen before include "Manufacture" , "Gather or congregate together" , "Bring or gather together" , "Gather or collect together" , "Gather together in one place" .)