Sure start maternity grant help?

at the moment i'm not eligible for this grant because of my boyfriend's high income and that i only get �10.37 tax credits a week and no working tax credits, however i was told i'd be able to claim this grant after the baby is born as my tax credits will be higher then, but apparently you only have 3 months after the birth to claim meaning i would have to register the birth, send off the child benefit form then inform the tax credits and apply for this grant all in 3 months! it seems impossible so now i'm confused? i don't see how people on jsa/income support who pay tax get this grant no questions asked, and i don't when my boyfriend pays �25000+ income tax each year!