I guess filling in the boxes with terms such as "Haven't a clue" and "Not even the foggiest idea" or "It was ages ago! Why would I remember?" won't really help.
I just want to pay the voluntary contribution. I mean I want to give HM Revenue and Customs money... Why would they make it so difficult? I'm sure they collect information just for the sake of it. I'll try sending in only one form (the one I can complete) and see what happens.
I still haven't heard from Jobcentreplus... I even sent the letter Recorded this time (sneaky huh?).