Its no use reporting to HMRC, people need to get the law changed and it will not be easy as its not just the model trade , its common practice in the trade in most retail type items.
It seems to be quite normal procedure these days for people to stock an item in the UK as a freight forwarder, the seller is outside Europe, eg. in China but delivery is made by a warehouse inside Europe such as the UK, Germany.
If you report it to the HMRC they say its quite legal, the transaction is made outside of Europe and the companies are just freight forwarders no UK transaction takes place only import and vat as they enter the UK, they claim the VAT back and then... often... some sellers... they value the item blow an amount required to pay any when they sell to you as value is what they pay for it...
Many of the sellers use the same companies to deliver, known as fulfilment centres.
I bought solar panels, laser cutter, stainless chemical reactor, bottle cap unscrambler from stock held in the UK or Germany this year and all delivered from UK stock but payment to UK or Germany sounding company location London or Hamburg, payment actually to China by paypal