I would provide NOA for last 3 years. Have seen lot of cases where sponsors had given consent through SIN# and even then CIC requested them for NOA/Option C. Also if you don't want to be their representative I would suggest putting their back home address. Also I think regardless of what address you put their file will be transferred to Ottawa (as of most of the cases who already have some kind of deal with CIC before are sent to Ottawa). Good luck.!!