Urinary Incontinence: Home Cures for Bladder Disorders

My dog has been urinary incontinent ever since he was neutered. At first my vet prescribed a medication to help control it, but after a while, it stopped working and I felt more comfortable giving him natural remedies instead. I've tried many different treatments, including a handful of bladder strength supplements and even apple cider vinegar. But nothing seems to work! He wears diapers now, but sometimes the diapers chafe his skin, so it's just a big headache for the both of us.

His leaking just seems to get worse too, and the vet has ruled out infections and says his bloodwork is normal, so no diseases that we know of. Is there any combination of natural remedies to help a severe case of incontinence?

I tried ACV on my 6 year old lab/whippet cross after reading about it here (mild relaxed/night-time incontinence manifested around four years after he had been neutered), it had little noticeable effect; but then every dog is different.

I have sourced some cornsilk capsules here in the UK, I'm going to try them on him.