Jogging my memory banks here...
The only time I've replaced an ignition switch on a P38 was in 1995-1997
The ignition key would get stuck in the crank position and cause the hvac and radio
to be off while running.
Here's a bulletin for it.
http://jimsrover.afraid.org/rover/Te...20Start-up.pdf
There are 2 different steering columns, Yours' most likely the newer version
Not saying you cant replace the ignition switch in it but for some reason
it was not recommended and I don't recall if I have replaced one on a newer column or not (it has been 15yrs).
Don't know where the dealer got the part number for you, but you're probably waiting for a steering column.
Not saying that the ignition swicth is not the problem with your draw but I'm curious.
Did you have any key in warnings illuminated on insrument pack with the key removed?
Was the Alternator light staying on with key removed
More info please