You haven’t received a “CCJ”, or a County Court Judgement. You have received a county court claim (which includes somewhat rubbish Particulars of Claim), to which you must respond by 29 July with an Acknowledgement of Service or a defence. If you file an AoS you have a further 14 days (12 August) to file a defence.
If you send CEL a Subject Access Request for all personal information they hold on you, the reply will include the original PCN. It would seem sensible to file an AoS, therefore, to give you more time before you need to file a defence, by when you hopefully will have received the original PCN.