Firstly, its a 54 plate, having only covered 30k miles, and has a very unique sound to it, which changes when the clutch is compressed to the floor. My thoughts are that the clutch is on its way out, as there is a whining sound that increases along with the revs, but there is no slip when driving and no feeling of grinding when the pedal is compressed. Has anyone had a similar strange sound from the car in these circumstances?
That'll be the clutch release bearing. Premature failure is often caused by excessive use of clutch e.g. holding the clutch in at traffic lights etc.
Unfortunately, it's about as much labour to fix as changing the whole clutch.
Secondly, the digital Odometer readout is disappearing! The mileage is losing some of its red lines that make up the numbers, making it almost impossible to correctly read the mileage. Is this simply a bulb that needs replacing? Or something else? Advice on how to fix would be hugely appreciated.
Difficult to say which part is failing ( driver, display or maybe dry solder joints ) but the LCD is probably failing. Easy fix is to try and get a used instrument pack with about the same mileage. Alternatively, it may be possible to get another pack and get someone with soldering skills to transfer the LCD display.
Thirdly, the automatic drop has stopped working on the drivers door when the door is opened. I believe this may be some kind of switch or something that may have given up the ghost? Is it a fairly straight forward job to cut the old one off and replace with another one, crimping wires etc? Obviously its door card off, which looks like fun also! :-)
The simplest explanation is that the cam needs an adjustment.
Have a look at this post
It'll give you some idea of the adjustment process.
If it isn't the adjustment that's off, the next likely explanation is that the switch has failed. That thread will will tell you everything you'll ever want to know about the autodrop window system including where to get replacement microswitches at a fraction of the price of AR parts departments!