Normally they require original bank statements or copies printed & stamped by the bank. You could drop in to the enquiries desk at your local SW office & ask them will online banking printouts be acceptable. You could offer to have your bank stamp the online printouts.
Depending on your specific claim they may or may not interview you, or they may decide to visit you at your home, but they will inform you of any further information they require & date of desk assessment/home visit.