Changes are afoot that will mean online sellers such as eBay will be disclosing users’ income with the tax authorities – HMRC in the UK. The same will apply to rental income so if you rent out via Airbnb for example, a property in Germany, both the UK and German authorities will be informed.
Ensure, if you are VAT registered, that you have the correct VAT number registered with the online trading platforms. If you have changed from an unincorporated business to a limited company and registered a new VAT number, ensure this is notified to the online platforms.
Beware too when selling online that the sale value for determining VAT registration purposes and sales on which VAT might have to be paid is the gross sale proceeds before deducting commissions and listing fees, and not the amount that ends up in your bank account.