The door on our dishwasher just drops when we open it. We are assuming that the hinges have broken, if so could these be easily replaced by a very competent DIYer? Could there be any other reason as to why this has happened? The dishwasher works perfectly otherwise.
Almost certainly a set of these nylon door bands that you need. They’ll have snapped but they’re reasonably easy to change although you will need the dishwasher out, with the power off and the side panels removed IIRC.
I had this problem on the same model a couple of years ago and called a technician in to repair it. The repair lasted about a year and then the cheap nylon components broke again. This time, I chose to replace them myself by bending a piece of a steel coat hanger into the shape required.
To answer the original question, yes, a determined DIYer can solve this problem.