I think the government will rebrand operators as they join GBR just to make it clear they've changed something. I think it'll be based on service type, like in mainland Europe. It seems to be the most logical decision. Also, the original GBR white paper mentioned unified branding across services. In my view, keeping the unusually fragmented branding would be confusing and make very little sense, especially because a lot of these brands (Northern, SWR, Southern, etc) aren't compelling at all, so wouldn't really be missed by the wider public.