Well, I'll take a stab at this since no one seems to want to. First of all, you say "recent vintage car". To me, that's a contradiction in terms. A vintage car is not a recent car.
If you have a drain plug or plugs at the bottom of the engine block you can remove them and drain the coolant out of the block. If you can drain the engine block as well as drain the radiator, you may not need to flush the system IF the car is new or fairly new. You flush the system for one or both of two reasons: (1) you wish to remove all the coolant from the system, which means you must remove it from the engine block as well as the radiator, AND you don't have, or can't find, or don't want to mess with, the engine block drain plugs, and (2) you wish to remove built up deposits clinging to the inside of the parts of the cooling system. With a new or fairly new vehicle you should not have these built up deposits.
If you switch from one type of coolant to another, you should be sure to get all the old coolant out before filling the system with the new, different type, of coolant, which requires you to either drain the block and radiator or flush the whole system, which flushes the old coolant out of the block and through the radiator and then into whatever you collect the flushed coolant in, such as a large pan.
