Update! They've mostly righted themselves with the exception of 2 which had a bit of help.
As for the big garden, it's not quite as simple as it sounds. It was an abandoned mess when I moved in, covered in self-seeded sycamore and ash that were absolutely enormous. The best guess is most of them were about 30 years old and the garden hadn't been touched in about the same amount of time. It is also incredibly steep, far too steep to put a mower on and far too full of rocks, broken glass, clay tiles and scrap metal. My lovely neighbour has spent most of the last year digging, clearing, building steps and paths and mostly being an absolute gardening genius. He's well into his 80's but still insists on carrying railway sleepers around and cutting them up with a handsaw to turn them into steps.
The brambles are definitely getting a hold. I'm about to sign out of work for the afternoon and go digging to see if we can get access to the fruit bushes again. One day, probably not this year or any time soon, it'll be lovely. In the mean time I just need to grow enough stuff to stop the thing looking like a muddy mess. If the chooks and wildlife can benefit from any excess, even better!