They stopped at Stansted because:
a) They were going from Farnborough (short rwy) to India, so STN was in roughly the right direction.
b) Several Antonov operators have good links with STN and can obtain very good handling/fuel rates I believe.
Is Newquay equipped to handle such a large aircraft in terms of infrastructure and equipment?
Can't see any operators needing to drop in there for fuel when going Westbound. EMA/STN/PIK are the usual civil UK airports used, plus Shannon and the Spanish/Portugese Atlantic Islands if required.