Thousands of items are available to buy from dealers online. Here we pick out one that caught our eye this week.
Roses in an Omega Pot by Duncan Grant (1885-1978) is among the works available on the site of Freya Mitton, a specialist in 20th century British art.
The oil on canvas, signed and twice dated ’56, is a recent addition, coming directly from a private collection in the Cotswolds. It measures 14 x 12in (36 x 29.5cm) and is available for £15,500.