Work is progressing nicely . . a little slower than I'd hoped but at least 99% of the digging is over with !
Work continued on the existing drainage arrangement to cope with the surface water run-off from the adjacent area . . .
The existing soak-away was small, blocked and backed up so I dug it up (not originally in the plan).
I doubled the capacity and increased the depth . . .
After that I finished leveling the main soil/clay area and extended the drainage trench a bit more . . .
At this stage (finally !!!) I can get a good idea to the eventual size . . . .
I exposed the connection to the first main soak-aways - more on that later . . .
Back to the smaller soak-away - I used 110mm drainage pipes (riddled with holes) to form the base of a drainage crate (to fit the hole I had) and wrapped it in membrane.
After that I added 10mm gravel to the bottom of the hole . . .
Added what will be the main pipe into the soak-away . . .
Sat the "crate" in place and back-filled the space around it with 20mm gravel.
I then added the next section of drainage pipe, adjusted for the fall, then back-filled around that with 10mm gravel, too.
The 5 bolts sticking out around the top of the soak-away should hopefully tie the surrounding slabs together when I do a mini-pour of concrete over the area to bring it back up to the surrounding level.