We have a series of excel worksheets whereby vehicle observations are made at a series of locations along a route. A registration number is noted at each observation point along with the time. This registration number is then matched at the analysis stage so we can calculate times taken between two locations. Some observers at the observation points record vehicle registration numbers correctly while others may miss a digit or transpose a digit. We would like a programme that create a new field containing the suggested correct registration based on data already gathered in the database and using a few basic rules we'll briefly discuss.