Hi Connemmara:
I'm an owner of two dogs and therefore I'm very sorry to hear of what sound like your doggie's separation anxiety. We had a dog years ago who could never be left without barking his head off, so I know exactly how you're feeling.
The legal position is basically that several processes would have to be gone through before you would end up in Magistrates Court. These are:
1. The barking would need to be deemed as a "Statutory Nuisance."
2. The Dog Wardens / Council would have to receive the initial complaint(s), which has obviously already happened in your case. Followed by a home visit (also done already).
3. In order to establish whether or not it amounts to "Statutory Nuisance", proof/evidence in the form of either recordings of the barking and/or written records of it would need to be gathered.
4. The complainant has to be prepared to make a written statement AND attend Court to give evidence. (this often puts a lot of people off).
5. Unless all the above criteria is met, you cannot be taken to Court, instead the Dog Warden would be restricted to offering you "advice". The complainant can otherwise pursue a private prosecution.
It's a pity if the complainant has not made him/herself known to you, otherwise you may have been able to resolve it amicably.
Hope this helps. The best of luck.