UC and occupational pension

I have informed UC about an occupational pension I receive and HMRC are reporting the right gross amount and also deducting income tax that gives me my take home pension monthly. My question is, should UC be using my gross or what I have left after tax as the amount deducted from my UC payment? Thanks.

Thanks for that. I will need to contact them as they have been using my gross pension and not my net after tax.