While investigating a slow emptying drain - into which my w/m empties and the rainwater from my kitchen roof runs - I discovered that the ceramic/pottery drain casing is broken in the sidewall. A large piece of the sidewall is actually missing and wasn't in the bottom of the chamber when I emptied it and unblocked the outlet, so I must assume it's been like that for quite some time. Behind the breach, a cavity has been eroded which I can easily get my hand into, although I can still feel the walls of this so it doesn't extend too far. Here's a photo that may help with my description of the problem:
Anyway, to my question, can a satisfactory repair be effected and what would be a the best approach, or should I bite the bullet and go for the much bigger job to replace the whole thing?
Thanks,
Jonathan