Chillie - several threads back as far as 2001 where we have tried to thrash out common vectoring/final speeds.
http://www.pprune.org/forums/showthread.php?t=3437 where post #66 seemed to be a reasonable compromise.
We also had
http://www.pprune.org/forums/showthr...threadid=15896 and
http://www.pprune.org/forums/showthread.php?t=123594.
These may be a start for you?