Blocked clay pipe removal advice

[barneybodger]

I got someone to replace a couple of leaking clay pipes that were connected to the down pipe from my roof guttering. In hindsight, I should have dug down before they did the job because having now done so I can see that there is a series of clay pipes going out into the street drain which is also full of gravel to add to my woes. I can see that one of the clay pipes has a hole in it and it's full of mud and roots, the builder made me aware that the first clay pipe he removed also had mud and roots in it so I am assuming thats the case all the way along. What's my best course of action here? Try to find a section close to my boundary where the clay pipe is intact and get an angle grinder to it? Then attempt to dig it out as best I can to meet the road, then fit a plastic drainage pipe with a connector at the plastic end and use the rubber joiner with the jubilee clips to attach the clay pipe to the new longer plastic section of pipe? Or get some advice?

 

[barneybodger]

Sorry missed a few of the important images