Be located in the heart of Docklands, that is (3)
I believe the answer is:
lie
'be located' is the definition.
(thesaurus)
'heart of docklands that is' is the wordplay.
'heart of' means to look at the middle letters.
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
The middle of 'docklands' is 'l'.
'l'+'ie'='LIE'
'in the' acts as a link.
(Other definitions for lie that I've seen before include "Piece of fiction" , "Fib - be prone" , "Prevaricate or recline" , "buried" , "Perjure" .)