I have a list of numbers:

900
1030
830 etc.

I need these in the format:

09:00:00
10:30:00
08:30:00 etc

I have tried text to columns but without the 0 before 830 the fixed width
line doesnt fall right.

Very stuck on this so any help would be gratefully recieved (otherwise I
have alot of work on my hands!!)