The options open to the creditor are listed here:
https://www.gov.uk/make-court-claim-for-money/enforce-a-judgment
If you're the debtor, you really, really, really want to avoid having your goods seized by bailiffs. For example, let's assume they seize a TV set that cost you £400. It's sold at auction, where nobody knows whether it's actually working properly or not, so it only fetches £60. The auctioneer claims 15% (£9) for his fee, leaving £51. But part of the bailiffs' fees (of perhaps £30) have to come out of that, meaning that losing a £400 telly only pays off £21 of your debt.