Last year around Christmas I passed the TC PPL exam. After that I took a pretty long break and recently returned. I haven't completed my flight test and I don't have my private license. Does the passed exam expire if I wait to long to get the PPL? If so, how long is that period before I have to write it again? Thanks

Right from the study and reference guide:
Examinations, including all sections of a sectionalized examination, that are required for the issuance of a permit or licence or for the endorsement of a permit or licence with a rating shall be completed during the 24-month period immediately preceding the date of the application for the permit, licence or rating.

You have two years from when you wrote the exam to get your license signed off.
RAT

Thanks mate! Much appreciated!