system separator markup position

[Neil Thornock]

In the following snippet, I've created an extra-tall staff, which is messing with the placement of the system separator markup.

Is there some way around this? Like moving the position of the system separator or assigning some different Y-extent to something?

%%%%%%%%%%%%
\paper { system-separator-markup = \slashSeparator }

<< {
    \override Staff.StaffSymbol #'line-positions = #'(14 -14)
    c'1 \break
    c'
}
{ c'1 c' }
>>