Hi aalimanan,
The guidance you have referred to only states that a Principal Place of Address is needed but this address doesn't have to be in the UK.
This bit of guidance is aimed at UK businesses who don't have a physical address as they are iterant for example.
For Non Established Traders the Principal Place of Business would be overseas and this is perfectly acceptable.
Please see the guidance again which helps you determibe whether a business is Uk based or a Non Established Trader.
9. Non-established-taxable-persons (NETPs) — basic information
Thank you.