Why would anyone suggest that a child with SEN should not be supported appropriately?
I'm not sure why you assume some of us have experience of this or dont believe in children being well supported, just because we think there may be other ways of tackling a problem than moaning at the school.
I have two hypermobile children. One EHCP with other significant difficulties including Hypermobility Asd and Dyspraxia(homeschooled since September due to CEV), one on iep but no other difficulties. I have a bit of experience in this area
Handwriting for Hypermobility is resource heavy and space intensive. You should be writing on a writing slope with a finger grip pen or pencil. In DS case he has a right to a scribe. (Before he was homeschooling) I could have been demanding school send all of these home, including the scribe.
Supporting appropriately should take into account circumstances, both person and school. It should also have an eye on the long run.
In the long run if your child is significantly hyper mobile, handwriting will die out (except for maths, although I personally can also type set maths). Handwriting is slow and painful, just isn't practical. You will give your child a significant leg up by learning how to make the computer work for you and the earlier you start this the more natural it becomes.
Theres more than one way of doing things
In a schooling environment that is radically different from the norm, handwriting might not be the most useful thing to be working on or pursuing. You can keep fine motor skills up via cooking, playing cards, computer games, lego, etc. You probably should be spending time squeezing a squeeze ball and making dinosaur footprints in play dough anyway.