The cyberattack was on a payroll system with current service personnel and some veterans. It is largely names and bank details that have been exposed.
I mean, that’s not ideal, but as information goes, that seems kind of limited. Bank data is maybe useful for someone trying to steal money, but I don’t see as how Chinese intelligence would benefit that much.
Maybe they could confirm that someone was working for the British military or something, like if they were working secretly for military intelligence? I don’t know if that’s something that the UK does.