One of my twin boys is left handed so I have seen first hand how much of a disability it is and how much it has an impact on their education.
My boys have always been extremely close in development and both learnt to read very quickly,fluent in rec.In many ways my left hander is brighter but my right hander is further on in school.
I am an ex teacher(mostly KS1) and literacy co-ordinator and I've been totally shocked at how little identification and support there is.
Itold the rec teacher he was left handed and have bugged every single teacher from rec to year 3 re his pencil grip.Nobody was the slightest bit interested or did anything what so ever to correct it. In the end I bought a pack of Penagains(fantastic,I tried all pencil grips and found this the best at the time)and took them into school insisting he use them and turn his paper.He still didn't bend his thumb but does now(he's in year 3) since I've made sure he turns his paper and relaxes his hand.
His twin is streaks ahead with writing and said left hander complained he hated literacy as he gets tired ie not being able to read what he'd written and incorrect pencil grip makes it a chore.His twin has beautiful neat and tidy handwriting,said left hander has always formed his letters correctly(due to my efforts at home) but to be frank getting legible hw sitting correctly on the line in the right size has taken many hours at home.
Poor handwriting has an impact on all areas of the curriculum.My left hander is streaks ahead in science,geog,history etc but his twin got higher sats results because he writes pages of beautifully written work.My left hander hates writing and finds it arduous so will just do a couple of lines.
I'm so very angry.This is an outstanding school and learning to write left handed is bloody hard work.These children should get the support they deserve just like any child with additional needs.Children should be assessed on entry and every half term.There should be goals,continual pencil grip checks and resources,other than scissors my son has nothing.
Happily thanks to me my son now has lovely handwriting that sits on the line with a perfect grip(no hooking).I now just need him to produce more 
.As I said he flew with reading but isn't putting his phonics(which he learnt to read instantly in rec the whole lot) into his writing so is still on Phase 4(his twin has finished/on the end of the whole scheme).I think because he covers his writing it makes spelling harder as you can't always see what you've written to check,(maybe forgets which sound he's put as it's covered up) or to get that jolt of recognition.I think it's an added complication when he's trying to use interesting words,keep his paper tilted,pencil held correctly and grip relaxed.
Sorry for the essay but I've been fuming about this for a while.