I was with Citibank many years ago. Due to having a surname which, being East European (former comm bloc) and almost matching some crazy Arab terrorist, prevented CB doing foreign transfers! They could not inspect the US blacklist; it was a database query only returning Y or N. Stupid system, not helped by a bank with stupid UK staff.
But now I buy using my UK company name and nothing has come up. Maybe it is people buying using personal names. They should set up a business name e.g. Joe Bin Laden -> JBL Systems.
I get a daily update from Ukraine and the amount of stuff is amazing. Large Altera and Xilinx FPGAs, various TMS320 family processors (Iranians like those for missiles). Russia and Iran will have stockpiled this stuff; it costs nothing on the scale of mil costs. But you can't stop this at all. Anybody can buy it.