Vendors - When do banks start asking questions about income? I use two banks, one I’ll say is monzo and I work multiple jobs so salary goes into each.

I take payment through bank from one person who basically likes the sell ID’s, and I keep the cash for doing the bitcoin. When will banks usually ask questions?

Also, what’s everyone think to the new vendor? Looks great and cheap, thinking I should make the next order with him instead of trusty g0d but not sure yet? Can anyone confirm Or deny?