My television is not what I thought it was, the manuals that came with it all those years ago are the wrong ones. According to the details burned into the back of the TV it is in fact a Sony kv-28ls60u and here’s the manual for it.
To access the engineer’s menu, to change the screen layout do the following sequence on the remote control when the TV is in standby mode:
i/?, 5, vol+, display
Then press menu.