I thought they were recording in a London studio?
That's what I heard. One of the tracks is an outlier... someone overheard the session.... its drum n bass, sounding.
I doubt all four would be in London. Adam doesn't live in London anymore, he's back in Danesmoate, which he has owned since 1988, and which is where a lot of the Joshua Tree was recorded. Edge and Bono both live in Killiney, even though Edge has a home in Malibu and Bono has one in Manhattan, and both share a villa in Eze. Larry Mullen lives in Howth.
My guess is the main recording location is Danesmoate. It's a private location, and would require media or fan attention on the bass player, so it's a great place to get away from any attention. It has three private entrances along with some back-door access through neighboring estates if needed, and it's right off Dublin's main ring-road, the M50. It's the perfect place to hide in plain sight.
My guess is they're planning on all going to Eze next month, where they have a recording studio. Larry and Adam both have homes within a ten minute drive of the main home Bono and Edge share.