Does anyone have any experience of this with their dog?

I had the other end of the spectrum.  My bitch had Cushings.  She had to have regular blood tests and had to take meds which were reviewed frequently.  Dosage changed quite often until everything settled down.  My vet said that if we didn't get it right it could go to Addisons.  But I'm not an expert on the condition, I just followed vets advice.

I have a pony with Cushings and that is so different.  She's in a lot of pain which I'm not sure is linked to the Addisons - waiting for xrays to be looked at by an expert

There is a lot of information  on Addison’s in Dogs if you google it. There is also forums for Addison’s in Dogs where you will get lots of help and advice .