Tax credits

[TheSunnySide]

I received a letter giving me a figure for the working tax and child tax credits I am entitled to. This week I have received two different payments which add up to more than £300 more than the figure given in the letter.

Is this an over payment or does the overpayment usually come in the form of a Miscalculation in the letter rather than an obscure amount in the bank?

Should I ring and check or just stash the extra in a savings account and assume they will Ask for it back at some point?

It'll likely be a back payment of money they're due you whilst processing the claim

Thank you. They told me today on the phone that it's the payment schedule not being set yet and there's another letter in the post to me dated the 7th but it will take ages to get to me. Weird.