Preheat the oven to 180C/350F. Measure your oats first, so you don't make a mess. Pour them in a mixing bowl. Add seasonings and stir until the colour is consistent. Melt the shortening and stir that in, making sure all the oats are coated. Now, you'll notice this stuff is pretty loose, and we need it not to be, so take 2T water and mix it in and just leave it for a few minutes. If it still feels loose, repeat with another tablespoon. You're unlikely to need more than 5T. Eventually, you should be able to press this stuff to the side of the bowl and get it to stick. That's when you get out your pie pan, dump this oat stuff in it, and start smooshing it around with a spoon. You should be able to coat a 9" pie pan with a moderate layer of oat gunk. Bake the crust for about fifteen minutes and then cool it completely before putting filling into it.
Dump the peaches in a pot with half a cup of water and put a lid on it. You're going to boil those for about 10-15m, until they're soft. In a different container, mix the other 1/2c water with the ginger, cornstarch, and sugar. Really stir the crap out of it until the cornstarch and sugar don't make lumps. Once the peaches are soft, dump that into the pot and keep stirring it! I suggest a fork. Somewhere in there, probably pretty quick, because it's a small amount of water, you're going to start to catch lumps. Just keep stirring them out until the whole pan starts to thicken up like a pudding. When the edges hit a rolling boil, turn off the heat and keep stirring for a minute or two. Leave that to cool to at least a temperature you'd be willing to put in your mouth.
Pour the pie sludge into the cooled crust. You're probably going to have to scrape it off the bottom and sides of the pot, because this stuff is really thick, which is what we want it to be. Make sure you've got that sauce into just about everywhere there's space between a peach and the crust, then stick it in the fridge to finish cooling. It should set, in few hours. Should. In theory. This is the part I'm up to. But, really, if it doesn't, then you have a fantastically delicious slightly runny pie, which is not the worst thing you could end up with.