Tax credits renewal help?

I have received my renewal pack and was about to fill it in but am a little stuck. My partner moved in on 28th august 2010 I reported the change on the same day my single claim was canceled and we applied for tax credits as a couple on the renewal form it is asking for my partners earnings for april2009-april2010 he was unemployed for that time and claimed job seekers allowance I'm happy enough to fill it in but he can't remember when he started claiming only that it ended the day he moved in also will this effect the amount of tax credits we receive because in that tax year we didn't live together. Also does anyone know where we can get the info on how much job seekers allowance he received in that tax year Thanks.