Excel 2007 :: Ensure Cell Postcode Have 8 Characters (including Spaces)

Excel 2007.I have a list of postcodes (UK) which have different lengths of characters (including spaces) from 6-8, however our system seems to add additional spaces inbetween the postcode, so it could have upto 11/12 characters (inc spaces) Below is what could come out:

EH21 6PQ - 1 Space (8 Char)
EH12 9HG - 3 Spaces (10 Char)
E1 8DF - 3 Spaces (8 Char)
LL5 1GH - 2 Spaces (8 Char)
L5 1FG - 1 Space (6 Char)

What I need is a formula to ensure each postcode only has 8 characters by inserting spaces between if there's less than 8 char and trimming if there's more than 8 char

So from the above postcodes the desired results would be:

EH21 6PQ - 1 Space (8 Char) - This would be correct
EH12 9HG - 3 Spaces (10 Char) - Trim off 2 spaces from the middle
E1 8DF - 3 Spaces (8 Char) - This would be correct
LL5 1GH - 2 Spaces (8 Char) - This would be correct
L5 1FG - 1 Space (6 Char) - Insert 2 spaces in the middle