OK, the deat toll of my new garden is still very much under control with just one deceased aucuba out of 3. Fatsia has survived thanks to your kind advice but now... It looks to me as if I'm killing the new edge.
Well the edge is formed by 40 cm high Buxus sempervirens, most them arrived home green with the exception of one that had developed a yellow edge on the leaves. Now the other 29 seem to be joining in. They don't look dry (but they wouldn't even if I were about to kill them), I have checked the soild is compacted enough around the roots but the little things don't get any better.
My box hedge did this when I planted it years ago. Was told that the plants are knocked back a bit by replanting, and it was to be expected.
Was also told to chop the tops off them all to ease the transition, encourage new growth next year, and make them bushier. Seemed a waste of money as you pay through the nose per cm of plant height! But it worked, and the following year the plants put on lots of new (entirely green!) growth.
It depends what you want the final height and density of the hedge to be. Chopping the tops off makes them put on new growth from the sides as much as the top, so they 'knit together' quicker.
Once they've merged, you can allow them to put on height. If you just allow them to grow unpruned for ages, they end up very gappy unless you've planted them closer together than the recommended distance iyswim.
If I were you, I'd only cut off about 5cm, just from the tops now, it being August. Then be a bit more brutal next year at the start of the growing season to encourage all that new growth at the sides.
It takes years to get a good hedge, but it looks fab in the end, so worth persevering.