The reports I have read, including claims here, were that an employee went there and used his old password that nobody at the City end bothered to change.
If that's true, it wasn't a 'hack' then. He maybe broke his contract clauses on conduct after leaving, and they exploited access that wasn't specifically granted, but does that really constitute a system breach?
If true at all, of course.
Which, if it is, is probably more likely why the club didn't pursue it much harder, rather than just being naively nice.