unreasonable demands from sons mum?

[midlandsman]

Hi, im after a little advice. I have a little boy and his mum and i live 4 hours apart. i pay regular maintenance (more than instructed to by the child maintenance folks). I see my son regularly for a week or 2 weeks at a time but things will become more difficult as he's about to start school in September. The agreement we currently have isnt a formal one but we work it out between ourselves.
Out of the blue today his mum came out with 'you HAVE to have him for every school holiday or alternatively pay my childcare bill while I'm working'. now, am i being unreasonable to think the childcare costs while hes with him mum aren't my responsibility? i have to consider my own childcare costs when hes with me and im working (im single) and i also pay a regular monthly maintenance amount which isn't insignificant. also, it goes without saying, i dont get enough holidays from work to be able to have him for every day hes not at school...
Just wanted a third party view on this.....
Many thanks

You pay £900 on top of having him 1/2 weeks and holidays etc...you pay for clothes etc in your home....and she wants you to pay for childcare as well?
No. You don't need to. You pay over the odds. £900 is more than enough to cover everything for 4yo boy! As for holidays..You need to know what the costs are at whatever she choses because it sounds like she's just pushing for more money. If he's with you, pay for a child minder or a recommended teenager with experience and maybe is connected to you or someone at work. Ask on a local fb page as well.

As a single mum, who never recieved child support I know how much she will need against what she claims she needs and she will have plenty. Any funds coming in will obviously pay her normal bills for your ds. Your ex then gets a bonus amount on top of that.
Did she ask you to pay towards childcare/nursery fees before he turned 4? In which case why would that change now? What happened in the 3 years before he went to school? Was his nursery 300 days a year? @midlandsman you need to know all these things before you agree to anything but either way...agree to pay for your own child care needs.