In October 2009, Matthew bought a piece of rare porcelain for £10,000. The porcelain was damaged in early 2016 and in February of that year Matthew spent £3,850 on restoration work. In July 2016, Matthew's insurance company paid him £4,000 and Matthew successfully claimed that this should not be treated as a part disposal. He sold the porcelain in March 2021 for £23,500. Compute the chargeable gain.