Hi James,
The symptoms on mine were that the fan would only stop or blow at full speed. After I plugged in the replacement unit it worked fine and has ever since. The screws were not the easiest to get in and out, I bought a cheap set of very long screwdrivers, 12inch long blades, from a low-cost tool shop that had magnetic tips and with care putting the unit back was much easier. The log screw drivers have been godsends on other jobs ever since.
The 03/04 part is diferent to the earlier one but a local Landy independant repair man tells me they are interchangeable, I cannot verify that as an official Landy dealer said they are not. I went for a new unit as I couldn't find a used one of the newer type but that was two years ago so there may be more around now.
Good luck.
Lawrence