| Fungal problems can be passed back and forth...you're right on that one. Also, the yogurt will help, just make sure you're getting yogurt that has the active cultures in it. It usually says if it does on the label. I don't know about the UK, but over here they actually sell psuedo yogurt with no active cultures.
Now this is probably old school, but when my kids were little and got thrush I was told to either wipe out the mouth gently with a warm cloth, or rinse with water after they ate or drank anything that had sugar. Today I would translate that into anything with carbs. The fungus feeds on sweet stuff. | 
