It would be highly surprising if BA's CAA inspectors, on call and in attendance very regularly, are not aware of incidents that affect the safety of the aircraft. Engineers would have been involved in a case such as oxygen bottles being emptied (IF indeed it happened) and would make instant reports on such matters both to the company and the CAA. This would be behind closed doors but anyone foolish enough to tamper with aircraft equipment would certainly face the courts, and equally certainly would be jailed.