Fleet insurance excess

[Drive train]

I am working as a courier for a company (as a subcontractor, not directly employed) on a day rate (often below minimum wage,which I'm informed doesn't apply as I'm not employed), and I caused some damage while reversing a van I was given to use. I have no signed agreement with this company at all, either regarding the work or the van provided to me.
Am I responsible for the £1000 insurance excess?
Also can the company take the money directly from the money owed to me for a month's work without giving notice?
Advice would be appreciated.
Thanks.

[Retromau5]

Without a contract that sets out the terms of you engagement with the company, I wouldn't have thought so. But the problem I see with this is that if you decide to object to this, then the company could just refuse you any more work leaving you even more out of pocket. If you're self employed, could you not ask for a cost receipt for the excess and claim it back on your self assessment?

[Drive train]

That's what I thought, but that's only part of the problem.
I need my money to pay my mortgage, if id had notice or arranged payment terms that would be different, but now im completely stuck.

[Drive train]

I think I'll have to pay it. Although I've been refused the right to see the fleet insurance documents, is that allowed? How can I be sure he's being honest about the excess?