"… it's not illegal to use them in your own home, but they won't pass a PAT. "
The third edition (2007) of the Code of Practice for In-Service Inspection and Testing of Electrical Equipment states:
"All standard plugs now sold are required by law (The Plugs and Sockets etc. (Safety) Regulations 1994) to conform to BS 1363, which requires pins to be sleeved. This legislation is not retrospective in that it does not apply to old plugs already in use, but such plugs should not be reused (i.e. not fitted to new cords)."
So unless the fourth edition (2012) changes this, which I doubt, equipment using unsleeved plugs should not fail PAT testing for that alone. However, I can think of no good reason for reusing unsleeved plugs, and recommend that they be 'brought to produce' to borrow the old Navy term.
George