Thanks again Hyacinth. It is difficult though because I don't know the owner and although he's very friendly about it, he just tends to walk away. But the last time he did stay long enough for me to give a similar sort of thing a go. The wolfhound was just standing there very calm so I'd bring my dog closer and closer but I didn't have any treats or distractions so I couldn't work it properly.
She's actually really good at playing with bigger dogs. She wrestles with and beats a GSD and a GD that are both at least 20kg heavier than her. She was just in the wrong place at the wrong time on this day and it seems to have drastically affected her. Luckily though, it's just these two particular dogs. Once they had gone another Irish Wolfhound came bounding over and she was fine with it.