The repair method should always follow the diagnosis, never precede it. A CCTV survey pinpoints the defect to the metre, grades it against the WRc classification and shows whether the pipe still holds its shape. That single piece of evidence is the difference between a targeted patch repair and an unnecessary excavation across a garden.
Localised faults — a hairline crack, a displaced joint, roots entering at one point — are patched. Runs with multiple defects along their length are relined end to end. Where a pipe has collapsed, deformed, or where a new connection is needed, the affected section is dug out and replaced with modern PVC or vitrified clay, then bedded and haunched in pea shingle or concrete depending on depth and loading.
After any repair the run should be re-surveyed and, where appropriate, water-tested. A post-repair CCTV recording is the proof the work was done properly and is worth keeping for insurance and for any future sale of the property.