No VAT will be charged on the hammer price, but VAT at 17.5% will be added to the buyer's premium, which is invoiced on a VAT inclusive basis.
Frank Dobson R.A. (1888-1963) and thence by descent
M. Eidelberg (ed.), Design 1935 - 1965, What Modern Was, New York, 1991, p. 95, pl. 122, and back cover (example illustrated)