​​​​​​​You can see it on the seat map, the old cabin on A350 has this staggered pattern for the 34 seats in a single cabin, rows 1 to 9. The new seats are all parallel and spread across 2 cabins as there are 48 of those, rows 1 to 14 with a galley between row 8 and row 10. Not always an exact science as you can always have an equipment swap. Row 1 is now called suite and that’s the ones that stay free for Ultis. If row 1 is full, seats 10 A and H are also very spacious as they have the bassinets. They are blocked in case someone books the flight with an infant but if still unoccupied, they get released about 40 hours prior to the flight, you can usually request the TA to move you there.