That won't become due for months. First the defence has to be sent by the CNCB to the claimant and they will acknowledge receipt of it and their intent to continue. After that you will have to complete your Directions Questionnaire and then there will be the waste time mediation phone call. Only after that will it be sent to your local county court where an allocation judge will review the case and make the necessary order. The judge will either strike out the claim, order further details, if necessary or allocate a hearing date. Once the hearing date is set, there will be deadlines for the claimant to pay the hearing fee, usually around a month before the hearing date and a deadline for submitting any witness statements etc.
Just be patient.