About fifteen years ago we bought these concrete blocks from somewhere in
north west london to make these shelves in the garden.

http://tinypic.com/r/250l2c4/7

The blocks are 10cm (4") x 14cm (5.5") x30cm (12") light stone coloured and
are dead flat on the working surfaces and 'rustic-bumpy' on the two face
surfaces.

We are wanting to build some more similar shelves, but cannot find these
blocks again in any places here in north west london.

Has anyone come across these or something pretty similar in size at least
for making more shelves. Thanks for any advice.