Your biggest problem is that making a submission out-of-time means the council can object to it, and they usually do. TEC then reject your submission. You can then request a county court judge review of the decision. This costs around £110 for a papers-based review and around £260 for an interview with the judge. Neither of these sums is normally recoverable.
You need to find out asap the status of each PCN, and whether bailiffs have yet been instructed for those registered at TEC. However I suppose as it is now 2024, they will all be registered.