
I think the jury is out re actual 'dangerous dog' notices. To some extent this is admitting you HAVE a dangerous dog. I have a notice alongside my front door which says 'I live here' and a picture of my main breed. This is as much to alert the authorities in the event of fire and us being out.
I totally agree with the fact these dogs shouldn't be roaming loose and that anybody has the right to gain access to their property, without running the gauntlet past two dogs like this !! If nothing else, dogs must be under the control of their owners at all times - which is for me, what makes it all the more tragic that a group of dogs mauled an elderly Lab, out with her owner, to the point she was so badly injured that she had to be put down. I gather nothing has been done by the police. I thought the police (UK) were taking dog on dog attacks way more seriously these days? The dogs are apparently still being exercised in the same area.
ps Indeed, the DDA covers attacks on private property (humans) now.