The episodes are available to watch online
I don't know if anyone else is still interested in this show but I used to really love it and I just found this site where you can watch them all online for free:
http://www.uktvbox.co.uk/index.php
Just type "Byker Grove" into the search box and it comes up with all the episodes from every series, except for the last five episodes of the final series - so if anyone has them or knows where to find them that would be awesome :)