If you are interested - some idea of what Chinese sellers do - and how it is killing UK sellers:
Chinese Retailer are being offered hugely subsidised postal services known as “Terminal Dues” by the United Nation’s Universal Postal Union (UPU) allowing them to sell goods including postage from China to the UK for less than the stamp would cost a UK retailer to send the same item from the UK...
www.vatfraud.org
Anything which comes into the UK with a value lower than £15 is exempt from VAT. It is exempt from duties if under £135 - but duties are typically very very low (single digit %) compared to the 20% VAT. Of course, even if the item is more than £15 - it is given a low value on the customs declaration so nobody pays any vat or duties. A large importer would be paying duties, and the VAT. yes, then can claim some of that back once sold on - but tax is still being paid.
Until one has actually run a business themselves in the UK - they have no idea of what the costs are. We won't even go into business rates - basically a tax on having a business premesis (similar to council tax) but for which you get nothing back for.