Statement of tax liability - The Netherlands

Hello, I have been asked by my Dutch pension provider to provide to them a Statement of Tax Liability. I am told that the UK has the right to claim tax on a foreign pension but in order to do this, need to have confirmation that I am a resident UK tax payer. I have a form here (downloaded and on hard copy) and I need to know who to send this to at HMRC so they can fill it out. I need this to be sent back to me, officially signed, so I can forward it to my Dutch pension provider. So please where and to whom do I send this form? Can this be done online? And do you have any idea what the turnaround time is for such things? Mnay thanks

Hi
This should be sent to:
HMRC,
PAYE & Self Assessment
BX9 1AS.
Thankyou.