Rogue is 6. She's began in the last 6 months or so to get quite snappy with other dogs.
Its usually when we meet another dog in the small path leading on to our dog field, or when there are a lot of owners/legs about and I think she feels a bit penned in maybe? She basically just whips round on them and gives them a very high pitched bark and mouths at them - I don't think she bites, but its very hard to tell.
Up until now she's been very placid really, very submissive (wees usually when we meet other people/dogs), and she only did the high pitched bark thing at HUGE fluffy alsations - and she would just take a very wide berth around them and run away

I'm not sure what has caused this - could be getting older? could be getting attacked in the park a few months ago by a dog (it was a pretty nasty attack), she also got pushed through an electric fence when playing with another dog about 10 months ago, and she thought the other dog had given her the shock
Any ideas how to solve this though? Owners usually whip their dog away and walk on. We have found if we let her 'play it out' she's fine in under a minute, but most people don't stay around for that long.