I would be inclined to email/phone guide dogs for the blind, explain to them what happened/where and description of dog.

It may be a problem that has developed and is being worked on, or it may be that this has developed and guide dogs are unaware of the problem. By letting them know you are giving them chance to help the lady and hopefully iron out this problem.
This is NOT acceptable behaviour from a guide dog who should not react like this to dogs. What happens if another dog retaliates? ... not a good scenario.

I cant imagine it will be too hard for them to trace her if you give them the area and dog description.

I've emailed them explaining what happened yesterday, just got to wait n see whats said.

Went out the same time today and didn't spot her x