Thanks ..I am hoping I can get away with 2 flexible rubber joiners and a new elbow. Hoping the flexibility in the joiner will be sufficient to adapt to the flattened shape.
The flattened pipe might (probably does) go back metres...into a steep rising embankment..not really viable to chase that back to where it might be ok..might end up right back to the collar!
Expect to get the bits I need this week.