Potential Large OVERPAYMENT- advise needed please

creditshelp

Hello all,
First time poster here and may be a little bit detailed but im thinking this is the best way I may be able to get the advice I need.
I have been claiming with my partner tax credits for the last 3 years. During this time I have been employed for 30 hrs a week on a low salary of around 8,000 per annum. My partner earns around 7,000 part time and we have 2 small children.
I own shares in the company that I work for, it is a new business which started around 5 years ago.
I have always given tax credits my exact figures and everything always corresponds to my P60 and so never had any issues.
This year I have again claimed based on the incomes above which have remained unchanged for the past 3 years.
My income to date this year is again exactly as expected and so payments have continued as usual.
However things could possibly change significantly as the company has recently worked on and won a huge contract and will make an unexpected but decent profit this tax year.
They have suggested to pay a dividend which would give me a very welcome decent windfall that I could use to put a deposit on a house as we currently rent.
I was over the moon at the thought of this payment ( around £20,000) but I realise now that if I get the payment in this tax year my tax credit income will suddently jump and will make my claim look almost ridiculous.
I have been paid my usual tax credit payments each month and my income has been the 15,000 per annum joint that we expected and I didnt know that an end of your payment would be on the cards.
So my question is, If I take this dividend payment this year and so at the year end my income is 20,000 more than expected would I be expected to pay back all of my tax credits in the same way as if I had falsely claimed throughout the year and had been earning a higher salary than I had declared?
I am simply unsure if an end of year windfall income is treated differently.
Also at what point do I declare this additional income as I am told that it will be paid to me on the last day of the tax year.
Thanks in advance for your help as I am in a panic over this!

creditshelp

Thanks for that.
Im guessing that means I will have to pay back all of my tax credits for the year.
It seems like this could be repeated for the next year too so i will advise them that aswell which means i wont have a claim next year to deduct the overpayment from and so I will have to pay it all back in one go is this right?

creditshelp

Thanks BB.
Without wanting to take up too much of your time what do you mean by circumstances of the award?
my award is based on an income of 14k which will go up to say 34k minus the 5k discounted
this will take up pretty much anything due I would guess.

creditshelp

ok great now I understand.
Also how and well should I tell them, do I just call them up now and advise im expecting an extra 20k this year and next and let me recaculate and cancel the payments?
I am also assuming if I do it this way rather than waiting for them to figure it out from my self assesment it will stand me in good stead with preferential repayment terms of such a large amount?