I've just had the other two out and was on my way back for the terrier when I met another dog owner who warned me to be careful going that way because there is a loose, dog-aggressive dog wandering the streets. His friend phoned him to warn him because it attacked his large breed dog, who is now in the vets being stitched up
He'd taken a big stick out on his walk to ward it off, but luckily didn't see it, however it was last seen wandering in an area very close to my house, so even if I went a different route to where we normally walk I couldn't guarantee not seeing it.
I've checked dog lost and informed the dog warden, who is out looking for it. They think they know where it is from and apparently this happens quite regularly 
If it started on the terrier he would not back down, he'd not offer any calming signals, he would fight to the death and this dog is larger than him.
I can walk him tonight after work but it wouldn't until after midnight. We can do some clicker training and fetch in the gated alley in the meantime.
WWYD?