First, thanks to everyone who have helped me sort my taxes out more...I'm slowly feeling more confident about all things US and UK tax related. One area that continues to perplex me is the best way to handle reporting worldwide income. Most of my UK income is reported via PAYE, but then I do have some additional income related to my profession, mainly in the form of honorariums and research/travel fellowships. These could be in different currencies, and are sometimes paid in cash or, if not, always transferred directly to my US bank account. I have diligently been reporting all of this on my US taxes as "other income." However, on reflection I don't know if I should report this on my self assessment too. I've asked other colleagues in my profession and it seems nobody does this--am I overthinking things? I should be clear these are always small amounts (max was £400) and the fellowships have all been to essentially cover expenses for travel to conduct research related to my line of work in higher education. I always end up at a loss on those once I count the actual expenses incurred on travel, so it's not like I'm banking here. The only other income, which again I already declare on US taxes, is a royalty check from a US publisher--this one is so tiny as to be laughable and it goes into my US bank account where it stays put.
That said, I do want to stay straight with HMRC but also don't want to overcomplicate or overthink the process. At present, I use the self assessment forms to declare foreign dividend income from a US index fund I hold with Vanguard and have not claimed the other income as I'd been advised by colleagues that this was not necessary. I find HMRC not particularly helpful for specific questions that cross US/UK tax rules and have read various opinions online that range from "leave it off" to a series of complicated steps.
On the flip side of this, I have read on the forum that I should be reporting interest from UK accounts. I don't receive much but it is higher than the normal $10 threshold applied to US bank account interest. I report the accounts on FBAR but did not realize I needed to report the account interest on my federal return and don't think Turbotax, which is the software I use, ever prompted me to do so. Do I need to go back and amend my previous tax returns? If so, is it for three years only? I use FEIE but reading old threads interest is not excludable under FEIE so don't know if that would mean I'd owe the IRS. I'd like to understand this rule in particular as looking into getting cash ISAs or a LISA so will start building up more foreign account interest to report in upcoming years.
Thanks for any and all advice! Every bit helps.