I took out the top bolt to see what the 'adjustment collar' was all about, and how it works.
When I did I realized what the manual was talking about and promptly replaced it.
For anyone who hasn't followed the thread closely, the 'adjustment' is between the sides of
the frame and the sides of the engine only, and it is supposed to be 0mm, or no gap at all.
And it only adjusts at the rear, there are no collars at the front, because the ability of the brackets
in the front to bend slightly side to side allow for the gap to be closed without them.
In the back the bolts go through a very rigid part of the frame which is not going to bend easily,
nor is it supposed to.
There is no other provision, either intentionally or otherwise, for the adjustment or movement
of this engine in this frame.
And no, it is not back together yet, but the solution will be posted here when it is.