The HV case is slid into the cut-out from the front. The HV board is slid into the aluminium extrusion and screwed in from behind as normal.  This way the board can be easily taken out if required.

The back panel is attached after cutting a slot large enough to take all the cables and the serial plug.  Connections made to the expansion board etc and the TW523 is mounted inside the case too (this is placed where the 2nd expansion board will go for convenience, but it can be moved to the space behind HV in the future)

Front view of the case showing the cut-out on the rear panel.

The lid goes on.

HomeVison in its new 19" home!