Repaying tax credits overpayment via UC

[Donkey14]

I have moved to UC from tax credits as much better off.
However I have received letter saying I owe £300 to tax credits due to overpayment from stopping tax credits part way through a month and having already bee paid efffectively, in advance for that month.
I understand where this overpayment comes from but how will it be collected? I have looked on internet and its so confusing. Some say I will have 25% of UC taken off til have repaid, some 5%. Others that it is based on my standard allowance, but what is this?
My first UC award was £464, how much of this am I likely to have taken off to repay this "debt".

They take off a small amount per month. It will be in your statement.

Hi I am aware they will take it off but how much? What is a small amount, £10,£50, £100?

It's 25% of your standard allowance

Ok so my standard allowance is £525, so they will take £131, even though I only get £464?

Are you single OP? Your personal allowance depends on your age and whether you are in a couple. Log into your OLJ and check.

Did you get an Advance Payment? Do you have any other deductions?

Hi couple over 25 so its £525 I believe. No other deductions just the tax credits overpayment.