Thanks for your reply. I've already came across your link. I guess my question was stated vaguely. Let me retry. For sake of simplicity let's consider a UK listed ETF domiciled in Ireland investing in US equity. I do agree that you don't pay any Irish withholding tax. By declaring them on your tax form you only pay UK tax on them. However, you don't get 100% of the distributed dividends. As mentioned in the your link from Deloitte:
So the fund gets only 85% of divs on which you then pay zero withholding tax to Ireland as said above. However, this 15% on the Fund level are lost and you pay then taxes on the remaining 85% in the UK, too. Now, at least in my home country (Switzerland) there is the following option: I could directly buy a US listed ETF. This has the advantage of lower minimum order amount (at IB). The US listed ETF pays 0 withholding tax to the US govi. Since there is a tax treaty between US and CH I get charged only 15% withholding tax. This can be done via IB using the W-8BEN form:
https://www.interactivebrokers.com/en/index.php?f=tax&p=nonus&conf=am
Up to this point we didnt gain anything (except smaller minimum order amount 1USD vs 10CHF). However, I've still lost this 15%. I can reclaim it on my Swiss tax form by getting a tax credit on my next tax bill. After all I really just pay CHF tax on the divs without double taxation.
It is quite an administrative effort required. On the other hand I'm obsessed with cost so I think it is worth looking into it. My question was therefore if you weren't aware of such a thing (not sure if you could reclaim the remaining 15% as an UK investor) or if its just not worth the hassle, i.e. stick to Irish domiciled ETF listed on an exchange in your home country.
If it is off topic here, let me know and I will remove this post.
cheers