The Nikon BS-N1000 is available as an accessory for the Nikon V1
for $3.95 - buy plenty...

I believe it's a design issue causing this cover to be too loose.
There is not enough upward pressure on the front catch (the flexible part)
to reach the hole on the top covers underside. The front catch should have
been thicker.

I have placed 5 small pieces of gaffer tape on the front plastic catch.
I used 5 pieces to get the right upward pressure, so it catches the hole
and now clicks in place with a nice click. This modification really works well.