It seems to be used to mean "back to the beginning".
A use is recorded in the Northern Ireland Hansard (parliamentary
record).
During a meeting (8 June 2011) of the Northern Ireland Assembly's
Committee for Employment and Learning Mr Jim Allister said (re
university tuition fees):
I am concerned that we are ending this session without a great deal
of clarity on the timescale or content of where we are going on
tuition fees. You say that you hope to put forward a paper
before recess, which is worrying in itself, but that it may not be
until after recess. However, it is clear that your paper will
include an option for increasing fees. That may be kicked back to
-> you, and we may then be back to “buts”, I suspect, and more time
lost. New terms are looming, and universities, parents and students
need to know where they stand.
From pdf file:
http://www.niassembly.gov.uk/Documents/Official-Reports/Employment/2011-2012/Overview%20of%20the%20Work%20of%20the%20Department%20for%20Employment%20and%20Learning%208.6.11.pdf
or
http://tinyurl.com/q33lem3
The entry for "but" in the OED doesn't give anything that could be
forcibly twisted to fit the idea of a "but" as a starting point.
"butt" is more promising. It was sometimes spelled "but".
One sense that caught my eye is:
butt, n.3
2. The trunk of a tree, esp. the thickest part just above the root.
1601...
....
1787 G. Winter New Syst. Husbandry 103 The tops and buts of ash
and oak are more advantageous for burning into charcoal than if
sold for firing.
So when literally or figuratively climbing trees "back to buts" could
mean starting from the bottom again.
(Just a very tentative thought.)
--
Peter Duncanson, UK
(in alt.usage.english)