I'm looking for suggestions for neatly connecting a 68mm plastic rainwater downpipe into a 100mm clay underground drainage pipe, ideally so it's easily accessible for rodding. The 68mm pipe is currently just sitting inside the 100mm pipe with a cement cover. See attached photos. It's hard to see from the photos, but the 100mm pipe is sitting just 20-25mm from the wall, which made me think inserting a plastic hopper might be tricky. All ideas welcome - except for excavating the underground pipe