Bank Accounts

Is it routine for the DWP to check with HMRC how many bank accounts there are in my name when I migrate to UC, or is this part of a review done on a case-by-case basis? I have four but currently only use one with the others having small amounts that do not take me over the £6000 limit. I will be declaring them all, but am interested if this is checked with HMRC with each individual's claim; and if this is likely to trigger a review? Will I need to have bank statements ready for each account, and how far back do they generally ask for account statements?
I care for a parent with middle to late stage dementia, and things are horrendous at the moment. I want to be as prepared as I can be and try to minimise any future stress if possible.

sorry to post on someone else's thread. but I am in receipt of 2 non means tested benefits ESA support group, no income related additions, and pip, both elements enhanced, I only have one bank account, a current account that pays no interest, same account that I have had since I was a teenager, no premium bonds isa's etc, I have above 16 k, I don't need to inform anyone if am correct? I don't class the money as savings, more rainy day money, I am expecting a tsunami this year as my wife is leaving me in June, I will be paying for everything. think I am ok, but a reassurance wouldn't go amiss, sorry for not starting a new thread, didn't seem worth it for the question, thanks

Hi, David,
Following on from my earlier post, I spoke to Citizens Advice Help to Claim Service and they said that migrating to Universal Credit (UC) is generally considered less thorough than making a new claim for UC, as migration often involves a streamlined process with additional checks to ensure you receive the same level of support as your previous benefit, while a new claim requires providing full details about your current circumstances and may involve more extensive verification checks.
So from my understanding of this, I would be more likely to have to provide bank statements for my accounts when a UC review comes up after being on the benefit for a period of time. Does this sound right? Or do new accounts being declared when migrating trigger a review? I am still a bit confused, but will start gathering evidence just in case.