I fly SQ all the time ,until covid it, as I live here.Made a mistake of flying BA once.Shower of shite.
They are using the A350 now for London. I flew to London just before COVID hit .For business class the seat is huge width wise. However when you make it into the bed the foot area is tiny and at an angle. Very weird and not so comfortable. Your flat but not straight .
Overall still the best airline by miles.Changi airport also fantastic. Im going to london in a few weeks ,looking forward to getting on a plane again.
Enjoy your flight with SQ