UK Taxation on US based retirement fund dividend payments

Hello I have a rollover IRA in the US which has holdings that generate dividends. These dividends are automatically reinvested and do not receive any cash from them. I've just realised that my UK based accountant is taking these into account for the UK taxes and I'm paying UK taxes on the dividends. As this is a retirement account that I have not taken any withdrawals from - is this correct? Or should the US based retirement based dividends be tax exempt in the UK as well? Thanks

Hi Kate Kehoe,
UK/US citizens resident in the UK, are taxable on their IRA interest in the UK.
The gross interest would be declared in your Self Assessment Tax return, using the supplementary page SA106.
The interest would be treated in the same way as UK interest and attract that starting rate of £5000.00.
Have a look here:
Tax on savings interest
DT19852 implies that tax is not payable in the USA on this interest.
Thank you.