Fully prepared to be told I'm unreasonable as I am currently fuming.
Walking my dog with my 2 young DC, in woods. Dog (inbetween cocker and springer spaniel size but much wider) comes pelting up, from behind runs into the back of my docs legs to get between them, then starts jumping on my dog. My dog tries to get away and looks terrified, other dog keeps relentlessly bouncing all over mine - no owner in sight. I end up shouting at other dog and shoo-ing it away. We carry on walking. 2 minutes later the dog comes back jumps at my DC shouted and dog swaps to bouncing on my dog. Again no owner in sight. I shout get your out of control dog under control, in the hope their idiot owner would hear and at least come and get their dog. Still no owner and dog won't shoo - I end up shouting quite aggressively at dog to leave and move toward it trying to force it away, my poor dog takes the opportunity hide behind me - other dog tries to follow - I move to block it shouting "no! leave it!" and chase dog away. This time dog stays away for a bit.
Then we enter a field. Once part way down, that bloody dog appears again and is now harrassing a very large dog. Large dog owner also ends up having to shout at the hooligan dog. Then another man appears at the other end of field and hooligan dog runs over to him. He strokes hooligan dog. Then hooligan dog comes pelting toward me and my DC and dog. I move out in front of my DC and dog and shout "dont you dare" at the dog start telling it to get away and try to shoo it off - it runs round me and jumps on my poor dog, who is clearly terrified. Man shouts "she's fine"! I shouted "is this your dog?!?" and he "yes and she's fine" and I shout "no she is not!!! get your dog under control! She has already been out of control jumping on and terrifying my DC and dog twice before this, whilst you were nowhere to be seen! Now get your fucking out of control dog off my dog before I leash her and take her to the dog warden as an out of control dog!!!!" He gets his dog back and leashes her saying "there is nothing wrong with her wanting to play"!!!! I was 
and furiously told him if that dog ever came near me, my DC or dog again I would put his out of control bitch on a lead and take her to the dog warden. It doesn't matter if she only wants to play if that actually just means terrorise and frighten other dogs and children, since that makes her dangerously out of control under the dangerous dogs act. He huffily walked off, dragging his dog with him, whilst his dog still lunged toward us.
I'm still and if I come across that dog loose and behaving like that again I really do want to leash it and take it to the dog warden as an out of control dog - would i be unreasonable to do so - especially if owner is nowhere to be seen like the first two occasions the hooligan dog terrorised my DC and dog?