Advice needed please re Tax Credit

Treacle_2-2

I 'had' a very part time job which I attended for occassional days for around 3 months as a bank employee to fill in when needed, providing it suited both the company and myself, this was near on 3 years ago. I haven't been asked to fill in for at least the last 2 years. Since then I have had a baby and circumstances have changed slightly. Anyway I received a letter from the company stating that there will be redundancies in Aug, and it will affect everyone. I received a phonecall from HR to say they wanted to do everything fairly and would I be willing to work the occassional days. Now, since having our baby I receive child tax credit and would I be right to think that even working an occassional day will affect that credit, also I am assuming the company wants me to work to an occasional day as it somehow affects the redundancy maybe?!
I have no interest in the job now and I can't see I would be due much in the way of redundancy, my gut feeling tells me if I go along with it I could be then confusing the child tax credit issue and be worse off somewhere along the line?
Any advice welcome please!!