Tax on US 401K distributions

I am a US citizen who has lived in the UK for over 30 years. I have been tax resident in the UK for all of that time. My parents - both US citizens who were always resident in the US - have died and I have now begun taking annual distributions from some inherited IRAs. US Federal tax has been deducted from the IRA distributions.I file both UK and US tax returns. My understanding from other forum posts is that (a) the distributions are taxed as interest in the UK and shown as interest on the SA106 (Foreign) pages of my UK tax return, (b) because I am a US citizen resident in the UK, both the UK and US can tax the distributions, (c) the UK will not give credit for federal tax paid in the US and therefore (d) the US is required under the UK/US Tax Treaty to give credit for UK tax paid on the distributions. Can you please confirm that I have understood this correctly?

Hi,
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Thank you.