presumably the space on the GV would be sold
by individual seat, and not a sole use charter.
First class cabin's these days are very private with little cabins effectivley, where as a GV's would have an open cabin set-up (or be very be claustrophobic/confined)
I can't see someone paying top dollar to share a PRIVATE jet transatlantic, as it becomes a contradiction in terms ?
I reckon about £15-20k rtn per seat ? for a LON-SEA
not sure how this compares with main line though