Reply To: Cancellation, downgrade, 2-1 voucher and re-route to different London airport

[AJA]

As for getting from LHR to LCY by public transport google suggests several options ranging in time from 1hr17 to 1hr40 so not actually impossible to get you to LCY 2hours later than originally scheduled although I accept that LHR is by far the more complicated airport to navigate. And not what you booked.