Sales by auctioneers and agents acting in their own name are treated as supplies both to and by them.
Where an agent acts in his own name and he is selling second-hand goods, he can use the margin scheme modified only in respect of the way in which the selling price is calculated. To the price obtained from the purchaser, the agent must add any commission etc. payable to him by the purchaser (HMRC Margin Schemes Manual at VATMARG 4050).
Auctioneers who invoice in their own name can either follow the above rules or alternatively adopt a special scheme for auctioneers which applies to both used motor cars and other second-hand goods. This works by the auctioneer: