I have lived the details Kaz, and could write the book
The vet (this after the third bout) advised latest thinking was to feed them through it.
I wasn't about to go through it again so instead starved Minnie for 24 hrs, then plain rice by the teaspoonful, increasing to a tablespoon.
Next day a breast fillet of chicken, chopped, same amount, with the rice.
Also really good/cheap is a pack of frozen pollock from tesco, dose as per chicken
Gradually increase.
For 5 years Minnie has been fed exclusively Burgess adult sensitive dry dog food, usually salmon and rice variety, sometimes Turkey, and has had no recurrences.
If we hear her stomach gurgling, we don't feed her, but that hasn't happened for ages.
Also feed 3 small meals, easier for the tum.
And NO treats, ever, especially no rawhide.
If that means Fraggle missing out, so be it.