I would pick the words very carefully. The last thing you want is for him to then be able to take you to court for slander of defamation of character.
Also, with the social media you will be alerting him to what is going on, especially if he doesn't turn up to court to find out himself. All it...
If you are taking him to small claims, then they may find in your favour (sounds like they probably will). If he still doesn't pay then you can ask the court to instruct baliffs.
https://www.gov.uk/make-court-claim-for-money/overview
To be honest, if he is doing that to so many people I doubt...