It’s 19% not 20%. Yes with LTD you always have to pay the UK corporate tax, no matter your customers or where you live. LLP does not have a corporate tax, every year companies earnings are payable by the shareholders in proportions to their shares. An LLP is a transparent entity, google that term, it means the company does not pay taxes, owners do.
With an LLP, for non-UK sourced income, UK does not care about taxes, in simple words. So in the UK you legally do not pay taxes. However, the issue is that LLP needs to shareholders (one could be a company you own) and you should still pay taxes in Cyprus. Plus, if the Cypriot tax man discovers that your company is tax resident in Cyprus, you have to pay everything like the company was incorporated in Cyprus. I think I read that article, the solution is not fully compliant, but you could get away with it especially if you have a small turnover and you do not tell the Cypriot tax man that you own a company in a fiscal paradise.
Think about the risks you are taking to save some money.
The only way to legally avoid to pay a corporate tax is to have a company in a jurisdiction where you are not living, share the company control with another person living in another country from the one where you live.
UK LLP with non-UK sourced income
owner 1 living in Cyrpus (you)
owner 2 not living in the UK, or in Cyprus
Corporation tax 0%
owner 1 pays dividends in Cyprus
owner 2 pays dividends where he/she lives
If you do the way of the article, Cyprus should not know about the LTD/LLP company you have in the UK. The solution he proposes is invoicing, which a way to do tax evasion. It was tax evasion before and after the CFC, with the difference that with CFC you are a bit more in danger. I am not sure if it has changed, but CFC works only for personal bank accounts.
This is a link regarding CFC rules in Cyprus https://www.ey.com/Publication/vwLUAssets/Cyprus_adopts_legislation_implementing_EU_Anti-Tax_Avoidance_Directive/$FILE/2019G_001559-19Gbl_Cyprus%20adopts%20legislation%20implementing%20EU%20ATAD.pdf
it seems if the company is controlled for more than 50% in Cyprus is tax resident in Cyprus.