Depends on how you want to define "securely". A sufficiently motivated attacker could attack the remaining encrypted data, either through brute force or exploiting a weakness in the algorithm.
Kind of like how if you explain a program like Medicaid, they're all in favor of it until you mention it's socialism and championed by a Democratic president (LBJ).
The article is new because the excavation just started, the home operated between 1920 and 1961. But it has happened in multiple locations in the UK. So, all of the above.
Even with the vast majority of people having no issues, with millions sold, that's still a good number of people just got a bad one. The article only reports two instances.
Depends on how you want to define "securely". A sufficiently motivated attacker could attack the remaining encrypted data, either through brute force or exploiting a weakness in the algorithm.