So my partner moved in on the 07/02/17 and before that he was working and I was claiming income support as a lone parent for 4 children. So I had to go from single to joint tax credit claim. So I had to make a claim for tax credits so my award is from 07/02/17-05/04/17 so it's around 8 week period for that year until renewal. They based our tax credit award on an income they found for my partner for the year 2015/2016 somewhere on their systems because I didn't have any of his p60s and he had lost them where he lived previously. So that income was 25204.00 but he worked very heavily That year whilst in his own and did massive amounts of overtime and because I knew he would not make that this year as he hadn't worked as much I asked them to change the award and base it on an estimate so I have his basic wage estimate for the year 2016-2017 as that's his basic wage without any enhancements ( working over 8 0 clock and sleep ins get added rate) was 19000 so that's what I thought to give to tax credits so I got payments based on that. He has now given me his p60 for that year and his actual income is £21568.00. So I'm now worried I've been overpaid a lot for those 8 weeks as well as provisional payments for this year ( although I did notify them a couple of weeks ago about the wage increase so my payments have changed to reflect this. )
So what will my award of 2016-2017 be based on if it was started on an income of 25204.00 and then changed to an income to £19000 to the actual income being £21568.00? I'm really worried but I didn't know what to do because i knew he would no way be earning the same as 15/16 income but wasn't able to tell exact income due to added rates so just gave an estimate. Does the 2500 income disregard still apply to estimates given?