Georges Seurat takes an eerie trip to the seaside, Yinka Shonibare puts empire in its place and Sean Scully reveals his source – all in your weekly dispatch

Seurat and the Sea
If you thought French 19th-century paintings of the seaside were all happy impressionism, you will be disconcerted, then absorbed by Seurat’s eerie modernist shores. Read the review.
• Courtauld Gallery, London, until 17 May