What cheeses me off

[AuSammy]

This is an interesting observation. I thought it was just me. I am overweight, although I do fit in a seat. But those SQ A350 Y seats were quite uncomfortable that I didn't sleep a good wink when I last flew SIN-BNE. My backside just got more and more painful as the flight went on. I guess if I had fallen deep asleep before a critical point in the pain, it might have been fine. Maybe I should have tried a window seat because at least I would have had a wall to lean on to offset the pressure on my lower back from the seat. I tried cushioning with the provided pillow or rolled up blanket, but that didn't work.

I'm more amazed that your short slim partner also found the seats uncomfortable. Here I was thinking that if I were normal and fit, I would have found the seat just fine.

You don't hear a lot of criticism about SQ even of their Y service, let alone seats, so maybe it's just us?

The squab seemed significantly shorter than usual so I felt I was sitting on the edge of the seat and pushed forward for the whole flight and felt like if it I didn't prop myself with the legs I would fall forward. Recline did not fix the issue. Got zero rest on the flight and very numb backside/ pins & needles.