Tricky one. Blind, old, not good with other dogs... New home or miracle needed

My name is Hessa and I live in Herts with my two children and many pets. At the moment I currently have nine dogs, 7 are rescues. I never intended to have this many dogs but I own a pet shop and people like to bring to my attention dogs that are living in bad conditions or need urgent rehoming. They know I will never give up on any dog and so this is how my numbers have crept up. I also foster for a rescue centre in Wales and kept two of my fosters as they had health issues and no one wanted them.
The newest dog into the home is Dink.

A man from a local kennels came into the pet shop and told me that a little dog called Dink and his Poodle friend had been boarding at his kennels when their owner sadly died. They had been living at the kennels for weeks while the family made arrangements. Dink is a Corgi cross who is aged 12-14. He is completely blind, although this doesn’t affect him, other than his cataracts he is fit and healthy and a great little dog.

The family had decided that they would take the Poodle but didn’t want to take on Dink and said that if a home couldn’t be found for him they would have him put to sleep. I couldn’t let this happen so I agreed to take him on.
Dink is such a fantastic little dog, very affectionate and well mannered BUT he is dog aggressive to certain dogs we meet on walks and to our Saluki Lily. We have tried all we can think of with him but nothing is working, we have also tried a muzzle on him but he hated it and kept yanking it off.
The way we are living at the moment is very stressful because Dink only has to smell Lily and he is whipped up into a frenzy, Lily is also very scared of him and it’s very upsetting to see. A couple of days ago he managed to get hold of her out on a walk and bit a hole in her leg, so he certainly means business. I now have to walk around the fields with him on the lead because I don’t want him to get hold of her or anyone else's dog.

We had a problem like this four years ago with a Yorkie called Ben that I took on, exactly the same thing, he was aggressive to our Lurcher (who has now passed away) he would pick on him constantly and made his life hell. Harvey (the Lurcher) sadly became ill and his last months with us were miserable because he was living in fear all the time. I contacted so many rescues but they all said the same – have him put to sleep.
I can see the same thing happening with Dink and I don’t know what to do or where to turn. With the same situation four years ago with Ben and Harvey I spent hundreds of pounds on trainers and behaviourists that we had found on the internet but no one helped us. We gave up in the end. I have tried to re home Dink through my shop, he would make someone a great pet if he lived on his own. Being blind he gets very wound up by the others dogs playing or barking and he needs a peaceful life. Sadly he has been rejected five times. People are put off by his age, they don’t want to take on a dog that might only have a few years left.
I feel I have many little options left. Having him put to sleep, for me is not an option. I would never give up on a dog because I know that they can change, and we have seen remarkable changes in our previous rescue dogs, but I don’t know where else to turn?
I wondered if you had any advice? Unfortunately I’m not in a financial position to take chances on trainers/behaviourists we find ourself on the internet and to be truthful, there are so many out there, how do you know they are good until they are in your house with your dog!?
Is there anyone you would recommend that would be willing to talk to me and possibly suggest some things I could try with him?
We care about Dink more than his family that had had him for 14 years and it’s so frustrating that people don’t tell you the dogs problems upfront, once they are in our house we won’t give up on them but we learn the hard way and so do our dogs.
Thank you for taking the time to read this email and I would welcome any help or advice that you have.
Hessa Riddett, by email