Do doors with overlapping swings violate building regulations in the UK?
I don’t know about the UK, but in the U.S. door swings are not regulated until you reach 10 occupants in commercial, institutional, retail, etc. buildings. (Residential and agricultural buildings are never regulated...well, there is a requirement about the size of an exit/entrance door from a residence.)

So, your doors might be inconvenient, cause bodily injury, be difficult to use in an emergency, seem silly, etc. they would not violate any building code in the U.S. 

Our codes are based on the International Code Council (ICC).