I'm answering my own question!

Just in case anyone's interested... or has an improvement.

Set TextAlign to 3. This fixes the numbers

For left alignment this works for me -

Function fixedlength(theString)
fixedlength = Left(theString & String$(10, 9), 10 + Len(theString))
End Function

ActiveWorkbook.Worksheets("Sheet1"t).Range("A1").V alue =
LTrim(fixedlength("12345"))