
Fail
"Remove the HDD and use a standard cloning process. Put the disk back and no-one would know any different."
And you would defeat the high-security tamper-evident seals how exactly?
"Can't read the data - not a big problem, there are various tools that can work their way through many forms of encryption. It may take a while but it can be done if you have the patience."
Yes, and do you really think a GCHQ system rated to hold TS material would really use one of those forms of encryption? Yep, you'd be able to break it, probably after 30+ years or so, assuming you had access to government levels of crypt-analysis processing grunt...
Cheers
Mark