Originally Posted by ff_flyer

I would definitely reroute if travelling in J.
No personal experience from this particular HiFly bird but according to various trip reports the hard product is inferior to AY.

DOH is too much backtracking (and probably more expensive for AY) to be practical and AY will most likely try to re-route via LHR.
With some preplanning you may get A350 for LHR-HEL leg, AY is operating the morning flight AY832/BA6032 dep. at 10:20 with A350 daily except Tue and Sat.
And a word of caution: several last minute changes from A350 to A320 due to technical reasons occurred lately.