Thankyou so much for all those links! I had no idea just how many agritourism options there were...

My sister Raechel and I sat down together and went through all of the links and search tools you provided and eventually found the place she had stayed at:

Agriturismo il Rigo, near Pienza http://www.agriturismoilrigo.com/index_eng.htm

Raech can't stop raving about it and is thrilled to have their contact details again.

So thanks very much to everyone for their help! Megan Brisbane, Australia