Helen,

I've just come back from the vets cos my Westie had the same problem.
He's got too much bad bateria in his large bowel (hence all the tummy rumbles)
He's had an injection and 2 lots of tablets. He's also got to go on a special diet proteins and carbs. (Awaiting that, but will send it on if you wish) but something like chicken, then pasta/rice or potatoes
Unfortunately Max is the most fussy-ist eater in the universe and yes we did things by the book with putting/taking the food away before anybody starts.
The vet reckons hes got psychological issues with regards to food!!