Maintain PR as a BC

Hi, I have a dual nationality BC and Italian, I was born in Italy and got my BC when I moved to the UK at 22. I was in the UK for 4 years and then I moved to Spain.

I saw reading documents of the HO that if you are outside of the UK for more than 2 years you would lose your permanent residency. Those same documents make an example of people that have dual citizenship by naturalization and I can't find anything that mentions if that would apply for my case too.

I am interested in this because it seems to me that PR is needed to to apply for a FP via Surinder Singh to move back to the UK with my non-eea wife.

Any sort of help or info on this would be greatly appreciated.

That only applies to non-EU nationals who hold indefinite leave to remain (ILR). They will lose ILR status if absent form the UK for more than 2 years. That does not apply to a British citizen as British citizens have right of abode in the UK and are not subject to immigration control.

Your non-EEA wife can come to the UK either under EEA regulation or UK immigration rules under family visa. Given that UK may leave the EU soon, I suggest not to go through the EEA regulation route to avoid the Brexit complications.