welcome
1st a CCJ does not expire, but after 6yrs since judgement should the claimant have failed to enforce it it become far more difficult almost impossible. the issuance of the intitial claimform also stops the SB clock so the debt never now becomes SB.
there is to all intent and purpose little Lowells can do, most certainly they are a DCA , a DCA is NOT A BAILIFF and has ZERO LEGAL POWERS on ANY debt no matter what it's type.
Lowell don't do doorsteppers but even if they did or get another DCA to do their dirty work, you are quite safe to tell them to leave y