After much searching of the forums and FAQs I haven't found an answer yet to my dilemma.
In iTunes I use the comments field for entering the CD serial number followed by the year of recording in closed brackets.
i.e ABC Classics 432 698-2 
However, for sorting purposes I wish now to batch convert all my music files so that the bracketed year of recording is at the beginning of the field followed by the serial number
i.e  ABC Classics 432 698-2
Obviously, whilst the bracketed year of recording will always be the same number of characters, the serial numbers will differ in both number and spacing of characters.
Therefore, is it possible to achieve this re-ordering, and if so how could it be done? I would welcome any ideas or assistance.