PE/WT+? 
Premium Economy/....... + 
.....with a Working Toilet + bog paper 
Those pretentious marketing idiots at BA call their "Premium Economy" product "World Traveller Plus", hence PE/WT+. On the A350 scum class (Economy/World Traveller) is 3-3-3 seating (9 across), whereas PE is 2-4-2 (8 across), so you get slightly more 'girth' in your seat. The seat pitch is also 38" versus 31/32", and being 6'6 tall that matters to me.
Thought of a few more....
PE/WT+ seats have tray tables built into the armrests, not the back of the seat in front. This means that when the cabin is empty (ok that might be unusual), you can't fold the arm rests up and lie cross the empty 3/4 seats next to you. Back in scum class you can do exactly that.
The seats are difficult to operate. Several people in my cabin had to call the big butch (poofter) steward to press the buttons to get the recline to work and un-work. The girlie trolly dollies weren't strong enough.
My seat seemed to be the only one with functioning IFE. Great for me you might think, but no, they kept resetting/rebooting the system to try and get it to work for everyone, which meant I lost my place in the film and had to start again. Only so many times you can put up with watching the same bits of Barbie over and over again.