Pete - I’ve installed two sets of the aftermarket pans currently available from the usual suppliers, and no problem accessing the pan bolts. The flanges on the engine pans stick out away from the rest of the pan. If yours don’t perhaps they’re old and the flanges have broken away.
JayJay:as I suspect either the pan cover or the engine pans are wrong for my car. Pan cover flange is very close to the bolt heads and the engine pans overlap some of the heads. Guess I need to change my thinking and get items that work right. Bill