Child staying in education, HMRC not informed

Hi, can anyone advise on this:

I have a client who didn’t realise they stopped receiving CTC for one of their children from Sep 2017 due to not informing HMRC that the child was staying in education.

I’m thinking about three separate tax years:

2017-18: Change of circs (child staying in education) was not reported. Can we do anything now? Final award notice for that year was only received in February of this year.

2018-19: Is this still called a change of circs, despite them being eligible from the start of the year? If it isn’t, can we simply request a revision of the final award notice when it comes?

2019-20: As above, but if that is not correct, are we limited to one month backdate from today?

EDIT TO ADD: I have to ask client, but if they informed child benefit at the time about the child continuing in education, does that help us?

My understanding is that it is the legal responsibility of the claimant to notify changes of circs to “the relevant benefit paying office”.

HMRC may well argue that your client was at fault by failing to notify the Tax Credit Office that her child was continuing in education. The fact that the review and award notices advise clearly that any incorrect details are rectified by the client means that your client has missed a number of opportunities to put the situation right.

There may be an argument that the information was available to them via Child Benefit, and that they should have acted on this, but recent caselaw ([2018] UKUT 392 (AAC)), has tended to re-emphasise the claimant’s responsibility to notify changes.

Thank you.

We spoke to tax credits, and inexplicably they have agreed to put the child back on all the way to Sep 17.

I’m waiting to see the amended award notices first though!