The beast

It was such a beautifully day today Lisa and I decided we would take the dogs down the shore for a paddle, I have had a few problems with Tyson lately , where he has gone for a few other strange dogs, I now carry a muzzle with me for such occasions incase I need to put it on him.
The dogs had a wonderful time chasing the thrown stones in the water, we had just finished and had the dogs on the leads when this guy suddenly appeared with a black Labrador. I shouted to the owner to call his dog as it was starting to come towards us and tysons lead was all wet , plus the grass was very wet where I was standing. Anyway the guy totally ignored me, You can see what's happening here,dog come up to us very erect Tyson feels threatened , I slip , lead goes through hand and tyson has a go. The guy does nothing I'm on the floor and the dogs are fighting,I'm still trying to hold onto Bruno while shouting at Tyson to leave and the stupid guy just stands there.
I eventually get up grab Tyson meanwhile the guy just looks at me and wanders off. The muzzle goes on I have an ALPHA talk with my dog, My neck killing me from where I tried to hold both dogs and falling over. So we get round the corner and low and behold the guy is there again with his dog, me now I'm not to worried at this point as Tysons got his muzzle on, but I again ask the guy to call his dog as again it is coming straight for us. Yep he does nothing, bloody great I try and be a responsible owner and you get some idiots that that just don't care.
I can safely say I'm totally pissed off with my dog and to make matters worse my neck really hurts. So if there are any dog owners out there that have come across the same sort of thing and have any tips as to what I can do , I could really do with help. Tyson is nearly 5yrs old has never been an aggressive dog, he has been used for socializing other dogs because his nature is so good, never instigated fights. So why is he starting to go for strange dogs.....