Hi everyone.
Yes in my case I am looking at around 4 years of backdated ESA premiums, I only qualify for the lowest one which is EDP, but even that over 4 years is around 3k. So these payments do add up over a period of time.
I would be surprised if filling one of these forms triggered a claim for UC, because the underlying ESA remains contribution based, its a IR topup not a new claim for IR benefit. Also they fixing something that should have been done years ago, so for that reason it should not be treated as a new claim either.