[R] 'persp' query

[Geoffrey William Heard]

Hi All
 
I'm creating some 3-D plots using the function 'persp', and have a query regarding the ability to make changes to the label of the z-axis.
 
There are two things I would like to do. First, the default setting places the label a little close to the axis for my liking. Is there any way of moving the label? I've tried adjustments with 'mgp' in 'par', but without success. The second is to change the direction of the label. Currently it reads top to bottom, whereas I would like it to read bottom to top, as per a y-axis on a standard plot. Is there anyway of doing so?
 
Would greatly appreciate any advice!
 
Much thanks
 
Geoff