Problems confirming my identity on Gateway

I am having problems identifying myself on the Government Gateway website. When I tried to confirm my identity, I did not have any documents they asked me for. I was born in the UK in 1964. I have been in Spain since 1987 and have Spanish nationality. I do have a UK NI number. I am currently applying for a UK passport, which I had until 2003. This may take a while as I am currently preparing the documentation. How can someone in my position go about confirming my identity on the Government Gateway website?

Hi,
To access and use many of HMRC's online services customers may have to verify their identity online.
Not everyone will be able to verify immediately as the service is in development and limited to questions about pay and tax from employment, Self Assessment, tax credit details, passport information, UK credit reference data, UK driving licence information and Northern Ireland driving licence information.
If your circumstances do not meet the current verification criteria, you can use webchat, phone and postal services to check your records, manage your details, and request assistance with an offline journey.
You can do so here - Contact HMRC
Thank you.

Hi, I am having trouble with the Government Gateway not verify my ID, I have a Gateway ID and a Password which when I try to gain access to my Government Gateway account, the system is stating that my personal details are incorrect or it cannot verify it, even though I know that I am inputting it correctly. I have even tried the app, scanned my face and yet I still get the same message. Please can you advise as what I need to do next as I have tried the app, I have tried online and I have also tried picture authentication the system is just stating that my ID Information is incorrect or it cannot verify it. I can assure you that I am inputting all the information correctly, Thanking you in advance

Hi seymourb,
We are sorry to hear you are having issues accessing your online account and regret any inconvenience caused.  
Unfortunately we do not have access to your records on this forum. For assistance you would need to contact the online helpdesk: 
Technical support with HMRC online services
Thank you.