I'm glad that you got your girl with no harm done. They do have a tendency to bolt and go into I can't hear you mode!
As for the harness we use the step in puppia ones as the Velcro and clip at the back and cannot undo , as we had the same problem with the just Velcro ones.
I will post a link to some on eBay that you might want to check.
Puppia Step in Harness | eBay