Hi all. We are under offer on a house, in front of the garage in the centre of the drive is the below ‘drain’. It has a galvanised metal grid 2ft x 3ft, under this is a 1ft x 1ft slotted drain cover and immediately next to this is a 1ft x 1ft solid metal plate. It has water in it and there are no pipes from the direction of the ‘drain into the manholes. The drive is flat so doesn’t appear to be used to drain the drive. The owner is in a care home and his kids have no idea what it is. Any ideas what it is? Thanks