Foolishly, I did the following:
Added a new data file on current principal.
On my mirror the drive letters don't match
The new file could not be created on mirror.
Mirror goes into suspended.
I deleted the new file on principal and attempted to resume but the mirror still needs to create the new file before it can resume.
I tried to use mapping & subst to trick sql into thinking we temporarily have the r:\ drive, but this didn't work.
Any other ideas?
Worst case I will remirror & take the lesson on the chin. But it would be nice to avoid as it's a fairly big DB over a fairly crappy line.