You say that you don’t have in default judgement, but you do have a judgement dated the nineteenth of September because the defendant doesn’t appear to have complied with whatever the court ordered.
Anyway, irrelevant because you have a judgement.
I assume that there was no payment by credit card because of their was, you could file a section 75 Consumer Credit Act claim with the Card company.
Section 75 put liability onto the card or finance company along with the merchant provided the transaction was over 100 pounds and under 30,000 pounds although even if only a deposit was paid by credit, section 75 applies to the whole claim.
It was paid by debit card you could always ask the bank to charge the card back on the basis that the service was never provided and indeed, was cancelled by the merchant but it’s not as certain as a section 75 claim because you are at the mood mercy and whim of the banks because there is no statutory provision.
The proceeding should have been in the name of Joanne Woodwardt t/a Halcyon Days because the latter is not an entity. It doesn’t have any assets and you need to go after the individual.
You need to make an application to court to change the name of the judgement although the court may decide they want you to start again from scratch.
You need the home address of the individual if you want to have any chance of getting your money back.