Vertical placement of title, tempo, segno

[Alasdair McAndrew]

Sorry for being such a pain around here... I promise that soon 
I'll leave you all in peace!

Anyway, my problem du jour: I have a piece which starts with three 
text elements: the title of the piece, the tempo indication, and a 
segno sign.  This last occurs at the first bar line, immediately 
after the initial partial bar.

The problem is that the segno sign is placed above the tempo 
indication, which I think looks messy.  My preference would be 
(from top to bottom): title, tempo, segno.

Here is an MWE for this issue:

--

\version "2.18.2"

\score {
 \new Staff {
 \tempo "Faster than possible"
 \partial 4 r4 \mark \markup {\small \musicglyph #"scripts.segno" 
 }| r1
 }
 \layout { }
 \header{
   piece = "A piece"
 }
}

--

How can I have the segno sign occur below the tempo indication?

Thanks,
Alasdair

--
Alasdair McAndrew
http://numbersandshapes.net