Only four designers remain and this time they have come to Painswick Rocco Gardens in the heart of the Cotswolds. This week they have to create conceptual gardens which will showcase their creativity and impress judges RHS judge James Alexander Sinclair and Chelsea gold winner Ann Marie Powell. Perhaps the most difficult of all garden styles, conceptual gardens are sometimes called the thinking man’s garden - they are like works of art based around a strong central idea. Which designer has a simple clear story to tell, and fantastic planting to secure a place in the final?