Hey Jindon.

I had a look at your code, and it gets stuck at the 

If .test Then
line, saying wrong number of arguments. Also the length of the string I want to return is not necessarily 5 characters.

Domonic's code is working fine so I am going to stick with that for now. Thanks anyway, it's good to see an example of how you would do it with a RegExp function as they currently confuse me an awful lot and yet seem very clever and useful if I could get my head round them