Salthrop House Basset Down, Wroughton, Swindon, SN4 9QP. Sophie Conran. Driving W on M4, exit at J16, take 1st exit signposted for Butterfly World, drive 2m, passing the golf course on your R, keep going up the hill, Salthrop House is the drive on the L. Fri 9, Sat 10 June, Fri 14, Sat 15 July, Fri 15, Sat 16 Sept (10-4). Adm £6.50, chd free. Light refreshments. Salthrop House is a manor house garden set on the edge of the Marlborough Downs. A tremendous variety of perennials, shrubs, borders and pots unfurl themselves across this romantic garden and surround the sweeping lawn. You can wind your way through the woodland paths, enjoy a moment of peace by the pond or visit the new greenhouse and kitchen garden