@sirbills,
You have a couple of options: talk to the dog owners or report them to your local authority.
On a side note, if these same dogs end up following the law as in being leashed. What is the difference if these dogs are now walked on a leash down the street or allowed to roam to your dogs? Will your dogs still go crazy making noise while in sight of being walked on a leash?
My dog does this, whenever someone is out walking their dog or the one dog allowed out without a leash is wandering. He does not know the difference and will be barking and running from window to window until they are out of sight whether leashed or not.
I do agree dogs should be leashed though, just thought I do not think having them leashed will solve your problem.