OK, well the article you read is correct (though I wasn't able to find it online). Foreign tax-advantaged investments are not subject to US exemptions from taxation. Add to that the fact that, once your total overseas bank/investment account balance tops $10,000, you're supposed to file an annual declaration of your non-US accounts with the Treasury Dept.

It's only foreign earned income (i.e. salary and a few other categories) that is subject to the overseas earned income exclusion. All other forms of gains, interest and earnings are supposed to be declared and have US taxes paid on them. (Actually, you have to declare your earned income, too, in order to take the exclusion each year.)

If you're concerned about the cost of an accountant, you may want to try contacting an enrolled agent in the UK. This is a specialized type of tax advisor, registered with the IRS and subject to Treasury Dept. standards of conduct. There are a few enrolled agents in the UK, and I suspect they may have some experience with UK-US tax issues. The website for the National Association of Enrolled Agents is here: NAEA : Home page where there is more information about the profession.
Cheers,
Bev