They wont be able to "check you out" The only information they will have is what you put on your application form, any information that the bank currently hold and what is on your credit file and in the public register.
Public Register: This will have gone from here once the IVA completed or should have.
Credit Reference Agency : Will have gone from here 6 years from when the default date and IVA date this data will have gone.
Bank Data. This ones a bit more tricky, they will have records of your old accounts, possibly any searches that they do to maintain your account too. Also many banks are part of a wider group of accounts like Halifax and Lloyds
They will also most likely share data
Going into the branch to apply might be the best way, but they can still say no. And they will still ask "The Question". It's how you'd feel answering that question truthfully in front of someone face to face you then have to consider.
My view on the question, everything on a application is "credit scored" by the bank. You need to know really how much weight they give to answering yes to the question, if it then precludes you from applying then why bother wasting my time and theirs. Trouble is the banks wont tell you until you do apply so you end up in a decline spiral further affecting your ability to get mortgage elsewhere
We're willing to wipe the slate clean, give you a fresh start. All that we're asking in return is your cooperation.
