DLA, Mobility, maintenence, tax credits,Share Care

My situation is as follows:

We have shared care of our two children (10 and 11) which I obtained through court (our children told Cafcass that they wanted to live with us both equally but she fought against it purely for financial gain)
The children live with me for 47% of the year to her 53%
My ex wife lives in a 3 bed council house, earns a part time wage of £20,500,
receives all tax credits (including disable premium for our eldest), high rate DLA and high rate mobility totalling £350pw meaning she has a total income of nearly £700pw
I on the other hand work part time and earn £230pw, have rent and council tax of £200pw leaving me 30quid a week to support my kids on. I have asked her if she can sign over one of the child benefits and give me a proportion of our eldest DLA and mobility but she refuses to. She sees the benefits as her money and not for the benefit of the children. I have no choice now but to apply to court for ancilliary relief, ie maintenence pending suit, spousal maintenence, pension sharing order etc
I really dont want to do this as it will incur considerable costs on both sides, which i know i can''t afford, i still hope that we can reach mutual agreement but we have been in this position for the past year so i''m not holding out much hope.
I just feel that our children are at a huge disadvantage when they are living with me due to the large disparities of incomes in the two homes. Her actions regarding our disabled son''s benefits are unreasonable. Basically implying that when he lives with her, he is 100% disabled but when he lives with me, he is able bodied as i am not entitled to any financial help.
Am I acting unreasonably and over reacting or is she genuinely being unreasonable.

DLA can be split

www.carersuk.org/help-and-advice/help-wi...its/carers-allowance

it is paid to the carer if you look after the person for over 35 hours a week I dont think they would pay twice the sum would be split