Sidetrack to avoid centre of Stratford (5)
I believe the answer is:
shunt
'sidetrack' is the definition.
(I've seen this before)
'avoid centre of stratford' is the wordplay.
'avoid' becomes 'shun' (shunning is a kind of avoiding).
'centre of' means to look at the middle letters.
The middle of 'stratford' is 't'.
'shun'+'t'='SHUNT'
'to' acts as a link.
(Other definitions for shunt that I've seen before include "Car crash (slang)" , "Transfer rolling stock from track to track" , "Move rolling stock" , "Move wagons around" , "Arrange wagons; minor accident" .)