Safety Wired all drain plugs, except the most important one, naturally.

Drilling a hole in the MGB Differential Drain Plug for the safety wire:

 

 Here is the differential drain and filler plug safety wired to the axle housing:

 

...and here is the transmission drain plug safety wired to... I have no idea what that piece is, but it moves with the transmission, so it's not just good, it's good enough. 

  

 Somehow when doing the oil change, I forgot to drill a hole to safety wire the oil drain plug. D'OH!

Here is a pic of the MGB differential plug removal tool Scot & I hacked up one late winter night in 2011.\; it's a 3/8th to 1/2 inch drive adapter which we attacked with a grinder to fit the square hole in the drain and filler plug.