In fact, the wording on placement of Nemeth Code indicators around spatial material has changed in the updated Guidance. [Wording that mentions "the margin" was retained for discussion of tables.]
See #8.b under Additional Guidelines on page 9 of the Guidance for Transcription Using the Nemeth Code within UEB Contexts. (http://brailleauthority.org/ueb/nemeth-guidance/Nemeth%20Guidance%20Final.pdf)
The Nemeth Code terminator that follows a spatial arrangement should be in cell 1 on a line by itself, preceded by a blank line.