Q.Brown Turkey Figs Turning Rusty
In the last 2 weeks the figs on my new tree have started to turn rusty. The lower leaves have also started to turn yellow and fall off. Seems to have coincided with giving it a feed of homemade comfrey tea. Nearby pepper and tomato plant have leaves turning yellow and have stopped flowering or dropping yellow fruit stems since receiving the feed at the same time.

Certified GKH Gardening Expert
It is very possible that the tea had been contaminated by something. I can't say what, but it looks bacterial. You can try treating with a fungicide. This article will help:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
This article will help you to care for your tree:
https://www.gardeningknowhow.com/edible/fruits/figs/growing-figs-in-pots.htm