Calm down, don't worry about it. CCJs cannot be applied like clicking your fingers anyway. Im in the process of filing for a CCJ against a former employer of mine who dismissed me unfairly and its not as easy as you think.
I have to prove I won my employment tribunal, thus meaning "Evidence", no probs, i've got the court hearing and final written decision. All im trying to say, is that they need proof and as of such not passing this onto you will be unfair. Let them call your bluff.
For £300 or their abouts, I don't think they would bother!! Bollox to them!!!