Cathay Pacific to use A350s next year according to that Aspire Aviation blog. Edited the pertinent bit
"The preliminary plan, still subject to change, also calls for the “selective replacement of a few B777 routes to current European destinations”, Aspire Aviation‘s multiple sources at Cathay Pacific said. The airline launched a 4 times weekly service to Manchester on December 8th last year.... Replacing the 3-class 340-seat Boeing 777-300ER with a 280-seat 3-class A350-900, for instance, provides the airline flexibility to either boost the flight frequency that business travellers prefer and generally carries a higher yield, ; or hasten the maturation process of these new routes by temporarily slashing short-term capacity in order to improve both load factors and yield. Should the airline ultimately decide to do so on such routes, the A350 will enable it to better optimise its product offerings to match market demand."
Aspire, it must be remembered, leaked the route launch. I can see i being used to boost frequency as the 80% full 777 becomes a 97% full A350 on the same frequency!