I hope you were able to resolve this. I'm sorry that no one answered your post. If you still have questions, I'd post a question on your regional forum.

I have a fatsia in zone 7 in pretty heavy shade. it is about 4 years old. Mine has been a very slow grower, but this may be normal. Mine gets a few yellow leaves that break off by themselves, or sometimes I break them off. This yellowing of leaves has not seemed to harm the plant, it keeps putting out new growth. The plant actually gets ignored as it is in a very out of the way spot and we have had unusually dry weather for a long time. Hope this is at least some help for you.

Thank you two so much for responding! Luckily, I was able to solve this with the help of a neighbor. A month ago, she said that I should rig it a roof for shade and see what happened. (Failing that, she was going to take it for her much shadier garden.)

So I put a plastic footstool over it and waited. And a mere two weeks later, it had new GREEN growth. Eventually, I cut off the yellow leaves, and it still looks great.

Now I'm wondering what to do when it outgrows its footstool. I need a footstool for giants. :)

Sounds like you need a permanently shady place for it. Maybe your neighbor will let you visit it if you give it to her ...:)