The PCN has obviously been lost in the post and it is at least a possibility that the same might happen to the Order for Recovery.
I therefore suggest you check the PCN on
https://tfl.gov.uk/modes/driving/challenge-a-pcn at least once a week, once the debt has been registered with the Traffic Enforcement Centre the amount due will go up to £249, as soon as that happens you can download
form TE9, fill it in on your computer (no need to print out, the court will accept a typed signature, and remember the applicant is Transport for London, not you) and tick the box to say you never got the NTO/PCN, then email it to tec@justice.gov.uk with the PCN number in the subject line.
When the amount due on the TFL website drops back down to £65, it means the PCN has been reissued. Let us know when this happens (you'll need to check once every 10 days or so after you've emailed TEC) and we'll help with a representation.
Any questions please ask.