Actually, one more stupid question: You have three keys on the foot joint of that last flute… From lowest is it C, C# D something? or is it Bb, C, C# or B, C, C#?
The Eb hole is always below the D hole. Maybe others can explain why better than I can. The Eb hole is used not only for sounding an Eb, but also for venting some high notes. It doesn’t have to be higher on the body than the D because it has the same effect as making the D hole bigger, thus sounding Eb.
The reason the Eb key is below the D hole is the same as the reason the F natural key (the short one, anyway) is below the F# hole, and the Ab key (usually called the G# key) is below the A hole. Keep in mind that there are two ends to each key, namely the touch end and the hole end. On the hole end, except on the low C and C# keys, the function of the key when not touched is to close the hole. Now, look at where the key holes are located in relation to the finger holes, and keep in mind that the longer the closed tube length is, the lower the pitch will be. When you sound a D, the closed tube length will extend to either the foot end of the flute, or the open C# hole at the foot of the flute, depending of course on how your flute is built. (Many flutes, including my Olwell, have the holes at the foot end for C and C# even though there are no keys for them.) Opening the Eb hole, which lies between the C# hole and the D hole, will reduce the closed tube length accordingly, and if the maker has done his job right this reduction will be just enough to raise the pitch from D to D# (which in these well-tempered days is the same note as Eb, although it wasn’t always necessarily so…) And of course, opening the D hole (by lifting your finger) will shorten the closed tube even further and sound an E. This is why some players choose to refer to the finger holes by the name of the note that is sounded when the finger is the highest one lifted, rather than the name of the note that is sounded when the finger is the lowest one closed. (In other words, what you are calling the D hole would be called the E hole, and so forth.)