What you see here are the supports for the Round Header Bar which will be attached
to the two existing bolts that hold the front anchor plates on, the other mounting point
is the small tab you see on the underside, you can see on the one on the right, this tab
hooks into the front of the bed frame square tubing and holds it all nicely in place.
Here is the RH mount fitted in place, the overhang also covers up the hole in the
end of the square tubing
And the LH mount in place, here you can see the button head mounting bolts
I thought I was rather lucky to pick up a used double bunk bed frame and then extra
lucky when I found the thick wall mounting tube that the outer black tube slips snugly
into including a short section that joined the two halves of the outer tube together.
Now before you say that is too high etc, it will probably have about a 12" removed
from the height, then when I am completely happy with it I will have it duplicated
in Stainless Tube , as I want to build a slide on Camper for the Bed, the Header bar
will need to be below the level of the Camper bed frame, all in good time !