I\'ve been trying to understand excel cells more and specifically their data types. If anyone is interested in the detail my investigation is in the numbered points below.
If you want to show preceding zeroes on a number, providing you have a fixed number of digits before the decimal point you can Custom format the cells as e.g. '0000.00'. This example will always show four digits before the decimal point and two afterwards; it has its limits but is very useful for e.g. product codes. if you standardise on 7-digit codes, set the custom format as '0000000' and '0001234' will stay correct (not '1234') and still be recognised as a number.