13/04/2022 Roofing slates from Welsh Slate feature on the Duchy of Cornwall’s Nansledan development. As work continues at Nansledan – the Duchy of Cornwall’s award-winning 218-hectare mixed-use urban extension to Newquay – Welsh slates are continuing to make their mark. Hundreds of Welsh Slate’s Penrhyn Heather Blues in two sizes – 500mm x 300mm and