They have to catch you first and I don't think they would be looking for something as unimportant as unpaid fines, unless of course it is an enormous amount. Wouldn't go back to my old haunts if it was me though.
Only in extreme cases would someone who had not paid a fine be subject to a custodial sentence, having said which I understand nearly 130 people were imprisoned in 2011 for non-payment of fines. Contact the court as a matter of urgency and explain your position.
Its unlikely that a commital warrant would be issued without a further means enquiry having been made by the court - but possible a warrant without bail for the means enquiry may have been issued.
I do not know how true to life Road Wars is but somebody was arrested for unpaid fines from 2 years before after being stopped in his car and was released after the fines were paid.
If I remember right the amount involved was £600.
He was stopped for a light which was not working.