This morning I received a random, one-off payment from tax credits. I assume it's some sort of back payment? I've logged onto their gateway and there's no mention of it. The only difference is that our regular payments have been slightly ammended from now on.
Is this the aftermath of April (new financial year) and only now catching up with us? Our last change of circumstances was a year ago.
It's a huge back payment. In honesty I'm a bit freaked out.
I don't have the will power, stamina or stregnth to call their monstrosity of a helpline! 
Anyone else had such a thing this time of year?