The Langdon bros are part of that arty group that PJ was friends with. Besides Spacehog, Antony has been in a few films, one with Joaquim Phoenix. Remember when Rose first visited LA and stayed at a house with a dinky pool (where she showed her arm exercises), and she proceeded to rip apart everything she saw. Hamburgers, Malibu beach shack, San Fran... you name it, she hated everything. PJ was there to schmooze and Rose was left alone with people having to drive her around. Anyway, Langdon was shown, along with his French photographer girlfriend.
Antony had an Insta account with a photo of Peej dressed as an old woman in rags, along with other silly pics. My impression was that PJ was the court jester for this group, and his photography allowed him entrance. He even managed to photograph Yoko, thanks to his Sean connection. Once you are allowed entrance into this world, the connections with other wealthy people in the arts grows (think Getty family).
There is no way in hell Rose will give this up to live as a divorceé in the country with a donkey and chickens.