grahammal wrote:
The number will never have leading zero's.
As far as I can tell it will always begin with a 5.
Examples
5393276
5393312
5393331
5393454

In that case you can change the formula in step 8 of my other post to:
=AND(ISNUMBER(F8),(LEN(F8)=7))
and leave out steps 2 to 5 inclusive.

Enjoy!!