hi all -- I am a DIYer who moved into a house in Northern Virginia three years ago with some high-end remodels that were done about 20 years ago, including a European-style wall-mounted, concealed faucet system in a first-floor half-bath. The faucet started failing today (water wouldn't turn off). All of the plumbing is behind drywall and wallpaper. To turn off the water, I had to remove a cabinet from a basement wall to access a panel in the ceiling where the shut-off valves were (fun stuff!) I am looking for help on what brand this might be and whether I can replace the cartridge (a) on my own, and/or (b) without having to remove drywall. AI (Claude) maybe-helpfully suggested this could be a "high-end European model common in the 1980s" (sounds right) and that it was likely a "Gessi 20100 Rettangolo" and wrote, "Gessi is still in business, still makes replacement cartridges, and their North American distributor network is active. The Rettangolo cartridges are ceramic disc type and are typically accessible from the front — the trim plate unscrews, the cartridge body is threaded into the in-wall rough valve, and it can often be extracted without opening the wall." But it said to check here for real advice! 
I'd greatly appreciate any suggestions. Photos here of the faucet handle removed, the cartridge protruding from the wall, and the access box in the basement. Thanks!
I'd greatly appreciate any suggestions. Photos here of the faucet handle removed, the cartridge protruding from the wall, and the access box in the basement. Thanks!
