[p4] Shrinking db.label?

We imported a biggish CVS repository.  It had probably about 250 or more tags in it.  This has resulted in a Perforce db.label file that’s about 1.2GB :-O

I have deleted many of the labels (it’s been determined we don’t need the old ones) but db.label has not shrunk.

 

Is there a way to clean some of this up?  Does it involve saving to and restoring from checkpoint?  (sigh)

 

Cheers!
Rob