Thought I would bring this to your attention, if you are not already aware of it.
My beautiful DD (2 tomorrow) has severe delay development in all skills - gross motor skills, fine motor skills, language, etc.
She is under various specialist hospitals (eye, hearing, development) and has portage once a week (which is wonderful for her).
My portage lady mentioned to me that I could claim LDA for her development delay but I never followed this up. After speaking to the Inland Revenue about getting help for childcare costs - long story - they asked if I claimed LDA and when I said "no", they said they would send the forms through.
They are very long winded but my Portage Worker filled them in for me (took about 2 1/2 hours).
Apparently it is awarded at 3 levels of payment depending on "disability" (I use that word lightly) and doesn't take into account income/savings, etc.
Just for those of you with "special" children, thought you might need to know that perhaps you are entitled to this.