DWP (counter fraud) Pre employment checks?

I received a provisional offer of employment with the DWP (counter fraud, AO grade) on the 16th Dec 2022, and am still waiting on them either offering me the role or not. My question is this. How long do these checks take usually and what part of the checks, are inclined to stop me getting offered the post?

I know my previous employers returned the references within a few days of receiving them (which was a few days after I was provisional offered the job) and a few days ago I was asked to take my documentation into the local job centre as proof (9th jan 2023). Its becoming frustrating yo gauge if this was the final process of the checks or not and I can't get a straight forward answer.

Can anyone help please as being a overthinker, I am thinking the worse case scenario (as usual) 🙈😊