Private pension - PAYE code

I have recently started to receive a private pension on top of my employee salary, so I am now told I have 2 sources of income and 2 tax codes. My employee tax code changed from CK1523X to CK1779X to reflect the extra income from my private pension. I assumed that this increase in tax code would be used to pay income tax owed, but I have now also received a statement from my pension provider showing that they have also deducted tax on my monthly payment. Am I being taxed twice? Will I receive a refund? Thank you

Hi Huw,
Hi it is hard to say wothout seeing an actual breakdown of what your code or both sources includes, it could be that your 2nd pension straddles the BR/HR bands so your main code may have been adjusted to account for this.
But really we would need to check your personal records, which cannot be done via this forum, you should contact the HMRC helpline:
Income Tax: general enquiries,
Thank you.