HS304 - USA Permanent resident pension income

I am a permanemt resident of the USA and have provided a 6166 residence certificate. I have pension income from when I worked in the UK which HMRC have confirmed is exempt from UK tax. My tax code is NT and no tax has been deducted. I think that therefore that I do not need to complete an HS304 claim form. and that I do not include in SA100 under question 11 and 12. Please can you advise if this is correct.

Hi,
As the source of income is not taxable in the UK and no tax has been deducted from it, there is no need to include on a self assessment tax return.
Thank you.