Moving a tempo mark to the right

[Anthony Youngman]

My usual moan about colliding markups :-)

Anyways, I've almost got this bit how I want it ... the following code 
has a rehearsal mark, tempo mark, and melody name all in "the same place".

    s2.*3 s1*8 \bar "||" \mark \default % 111
    \tempo "Languidly"
    \once \override TextScript.outside-staff-priority = #2000 
<>^\markup { \halign #-1.1 \small "The Last Night Of The World" }

The melody name is successfully moved up and to the right such that it 
no longer collides with the rehearsal mark, but the tempo mark still 
collides. The docu for halign says that it doesn't work for some marks 
(because they contain their own alignment code), and it looks like tempo 
is one of them. So how do I move a tempo mark to the right to get rid of 
the collision?

(Yes I know - there's no "minimal example", but the question basically 
is "what property moves a tempo horizontally?")

Cheers,
Wol