Claimed a tax credit incorrectly... Am I in trouble?

I was reviewing my tax credits online, adding a couple in and realised that I had claimed for something last year that I should not have. It was a silly mistake.

I mistook the income continuance credit for a healthcare policy credit. It is quite clear that I was wrong from the name alone, although in my defence when I applied last year it was not in the same format and name as it is now, it was a bit more vague and an idiot like myself din't properly research it.

So, I removed the credit for last year and this year, and I suspect I will likely owe money back. I don't think the money owed will be devastatingly high, but does anyone know if I will actually be in TROUBLE for this or will it be seen as a mistake and rectified by getting their money back?

Thanks

Don't worry. Just ring the tax office.