I am a mother of two girls aged 3 and 5, got my certification in teaching Mandarin as second language by National Taiwan Normal University. But honestly, it will be my first time to teach, cuz I had been working in intl' trading before having children. if your kids are about the same age and you wish they can learn Mandarin lively in homy atmosphere, here's my idea. One and half hours, twice a week. In first half hour, we can tell short stories, sing songs or play games with each other's kids in different corners or rooms. Then let kids play together in the rest of time (then we can have our morning high tea:)). Occasional subjects and activities such as little chef are good idea as well. Anyway, anyone is interested, lets discuss further.
BTW, we like travel and hiking, normally would go hiking in weekend, just back from one month journey in central Europe. It will be great if we share common hobbies. We live near by "Keyuan" underground station.