Hi stu2012
The DWP do say that you don't need to send in previous information, and plenty of people will say this has worked fine for them. Other people are not trusting of the system and send it all again. This is a decision you will have to make for yourself and what feels right. Personally, I would only send in new information.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems