You can build it by making sure your normal payments are up to date. If you want to apply for credit make sure you do a soft search first so it doesn't show up on your credit record.
It will return to excellent, mine did.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk