Dig earth bank out

[TryAgain1]

I'm digging an earth bank out to widen the back of a garden I should be able to gain about 120cm flat land. The original earth retaining wall is inward of the actual property boundary. I am digging behind the earth retaining wall (65cm high).

The issue is what to do with the remaining earth bank wall. I have tried to slope the 120cm high earth bank diagonally down so the bank does not fall over. There are bushes and large plants growing at the top of the bank which keeps the soil together.

I don't want to rebuild the earth retaining wall 120cm back as this is a lot of work. Can I instead pin weed suppressant sheets over the slope? Can someone please suggest what to do to shore up the earth retaining wall (other than rebuilding the earth retaining wall)?
Thanks

Photos below

 

[Ivor Windybottom]

If you're removing the wall you'll need a new wall. Which will need to be taller, and therefore thicker, than the one you're removing. If you build on the boundary then you'll need agreement from the owners of the adjoining land.

You can't just dig it all out and drape some magic membrane over it.

It sounds like a lot of effort for little or no gain. It looks fine as it is to me, you're in danger of creating a boggy, collapsing ditch.

If you want a sloping bank then you'll need a shallow slope. It looks like you'll just end up with a load of mud all over the grey path or driveway.