As part of some work the County Council were doing on FLOWS (see: www.flows.nu/ and www.cambridgeshire.gov.uk/environment/sustainable/european/flows/ ) they put together (for trial purposes) some mapping of drains - see: map1.cambridgeshire.gov.uk/mapportal/mappage.asp?application=flows&xT7512&Y&2736&z%00 for the area around Milton. Denis (lurking from Impington, but involved in some of this work)