We're currently having a conservatory fitted by a local contractor. In digging the foundations that run close to the bottom of our SVP stack, they broke the ceramic/clay bend at the base of the uPVC soil stack. The uPVC pipe used to sit inside a lip on the clay bend but they've broken off this lip for about 1/4 of the diameter which has caused water to leak out at the base of the soil pipe whenever the toilet is flushed. I pointed this out and their repair consists of piling some cement around the base of the pipe where the clay bend has broken. Is this satisfactory or should I be getting them to replace the bend? I'm not particularly happy with it but don't know if I'm worrying about nothing?