Wilma has had diarrhea since Monday. There has been no change to her kibble, but on Sunday she did drink some milk at the 'in laws' house

and on Monday morning walk ate some chicken (?) which she found on the floor when off lead....probably some discarded takeaway.
Every time she poops it is loose, or watery/greasy. Also she Has diarrhoea through the night. There is no blood. It can look gel-like at times.
Apart from this she is full of beans. Drinking well, gums look healthy. Still running around house cocker-style, and eating her kibble. She has not vomited and hasn't shown any abdominal discomfort when we groom or lightly prod her in this area. I have stopped giving her rawhide chews and told everyone to not give her titbits (which we have been guilty of). She is wormed and vaccinated.
I am willing to pay for vet treatment, but equally don't want to start her on antibiotics unless necessary...in my experience every vet visit includes a shot of antibiotics 'just in case'. Do you hunk his is serious? If so, I'll be there like a shot.

I haven't tried boiled chicken and rice diet yet so may give that a go today and see how we get on for 24 hours. If that doesn't work, ill book appt for tomorrow. Does this sound reasonable to others given that she is bright and alert?
Any help/guidance would be appreciated.