File Guidelines

There are a few simple but important guidelines for preparing your telephone numbers for cleaning.

Your file will be matched against one or more of the preference service registers using an automated process. The register is compiled from full UK area code and telephone number only. If your phone field contains any information other than this a fully correct search may not be possible.

If you need help to re-format your telephone numbers please contact us.

Please Remove:

• International dialling prefixes e.g. +44
• Telephone extension numbers
• Database control characters. If any of these characters are imbedded in your file it is unlikely that you will get an accurate result. This includes carriage returns within data fields.

Your telephone number file should:

• Be in a plain text format , either .csv or .txt. The easiest way to do this is from MS Excel. When you have prepared your numbers, use File/Save As and select Save As Type ‘CSV (comma delimited) (*.csv)’ below the file name you have entered before clicking Save.
• Contain telephone numbers only – no other data
• Contain telephone numbers in full UK format, including the leading zero e.g. 01451 860105
• Contain a space somewhere in each telephone number to ensure each number is delimited properly when you save file in a .csv format e.g. 020 8420 4242 or 0845 555555. If numbers do not include a space, the leading zero will be deleted in the process of saving the file in a .csv format
• Include only numbers 0 (zero) to 9 (nine). All other characters are ignored. Please be very careful with your data as a number such as "0207 456 7945 (ext 22)" will be read as "0207456794522" (notice the 22 has attached itself to the end). This is because all of the other characters are stripped out. 0207 456 7945 may be a listed number but 0207 456 7945 22 will not flag as a match. Spaces, commas, hyphens, brackets and slashes may be included as they will be ignored by the system.
• Be a maximum of 2 Megabytes. If you file is larger you can split it up or contact us for help.
• Files must contain one telephone number per line. An example of a file opened in Notepad is shown below.