The single biggest mistake you made was ignoring the county court claim. That act alone handed them a default judgment on a silver platter—and with it, you proverbially blew off both feet, your arms, and your face in one clean shot.
Transferring liability may have been valid, and the operator may have accepted it, but none of that matters once you let the claim go unanswered. You forfeited your right to contest, defend, or even explain.
Now you're dealing with High Court Enforcement, which is the endgame—not the beginning. No amount of moaning, hand-wringing, or forum sympathy is going to reverse a judgment that you allowed to crystallise through silence.
You need to stop digging and start climbing. You’re in a procedural grave you dug yourself. Get professional legal advice immediately. You’re in a self-inflicted procedural mess, and only someone who understands the mechanics of set-aside applications and enforcement protocol can help you now.