Hi rhiannwales
If you can not get the IEP or are not willing to wait for the school to have their act together, look into some Handwriting classes or camps. I know they have them her in PA not sure if they are nationwide. If not look into using OT from a private pediatric therapy practice, you could talk with your DR and see if it is covered on insurance, usually only so many visits are covered but it would at least get him started and not fall behind.
I used my insurance for my DS's PT and OT until my visits ran out then I went through Early Intervention and IU (the state/school program).
I prefered the private but that is just me!
Our OT/PT/ST practice has summer camps and does the handwriting(HWT is the program they use). My eldest had OT from preschool to beginning of 2nd grade. He did the summer program, actually his cursive is much more readable than his printing ever was.