I am trying to figure out which A350s have the loft and which ones have the booth. I tried looking it up but couldn’t really find anything. Has anyone got a conclusive up to date list ?

There's only 2 A350's in the leisure config with 16 Upper Class seats which have the booth, they are:
G-VEVE
G-VLIB
These are currently op'ing the MCO routes both from/to LHR & MAN.
All the other A350's are in the other config with 44 Upper Class seats which have the loft:
G-VLUX
G-VPOP
G-VPRD
G-VJAM
G-VDOT
G-VRNB
G-VTEA
These are all op'ing a variety of routes to/from LHR.