Ok, so the unblock didn't go to plan? or you knew there was a problem?
Patch Lining
Patch lining is a quick and effective way to repair minor faults in underground drains, however, most patches have a 50-year life span rather than over 100 years compared to PVC drain. Also, a patch can go wrong and may need excavating any way. We would only recommend patches if the line runs under a building and has not collapsed.