You don't say what age your daughter is now, but as far as her education is concerned, it would be assumed that she had finished in full time education when she got her degree in May. I am sure that his circumstances would also have changed, like everybody else's has with levies etc.... and % wage cuts???
Was he paying a large sum in maintenance to begin with. Are there other dependent children??? It is very unlikely you will be granted anything for the period between June to September... A trip to court might cost more than any maintenance being awarded, unless of course you have 'free legal aid'.