Walling

The problem was highlighted  in this blog post .
And in the meantime I've been pottering on when  its not been too muddy. It has helped that  it is staying light in the evenings.
So after brief goes at it,  over several evening  and a more concerted effort over the weekend, my first attempt at walling is done.
Before putting the coping stones on ,
-its solid enough to stand  on without things moving and falling off
-I've tried to put through-stones into the backfill at regular intervals 
-I've tried to lean it into the hill a little.
-in retrospect I probably should have removed  more of the  hardcore  from behind the wall

Before

After

And don't look  too closely at this one !