Much as the 'nasty' bit of me would like to see you send the bailiffs in, you probably wouldn't get much money from doing so. For instance, if the bailiffs took a telly that cost £500 it might only sell for something like £80 at auction (because potential buyers wouldn't know whether it was fully working or not). If the auction room takes 15% that only leaves £68 but the bailiff's fees would then have to be taken off, possibly leaving you with less than £50 from the sale of their telly.
Putting them through the inconvenience of having to attend court to explain their financial situation might be a better idea, as it would at least give you some idea of the best way forward from there.
So, if it's actually getting some money back that you're really interested in, force them to attend court. If it's simple revenge for all the hassle that they've caused you that's your real priority, send the bailiffs in!