Multi man ADR

Seems there are companies willing to use drivers who don’t know all these regulations to cut costs perhaps?? On this occasion we went up north delivering around Derbyshire from Heathrow I wasn’t happy to drive the first bit as there were four barrels of something with a dangerous goods logo on it (that really is all I know at the moment) so other driver drove up there got rid of that, then I drove next couple of hours etc… I wonder if this is common practise?