I have been paid but I'm not really sure how.

I think, at the prompting of a kind and generous well-connected person, that a regulatory intervention at senior level might have been made. Certainly, the issue was mentioned to a well-connected person, and the next day, I received notification that payment had been made.

It could have been coincidence.

This information is not useful to you in your quest for payment, sadly.

Did they make any attempt to defend themselves against your case? Have they been in touch since you obtained judgement?

In my (limited) experience, unless close to bankruptcy, companies are eager to make contact, pay up, and get a judgement marked as satisfied, once one has been obtained. Indeed, the former Northern Rail ("Arriva Trains North Limited") paid twice - once by accounts payable, and then again by their solicitors - such was their eagerness to clean their public record.