If you're having random disconnects with the Enhanced Wireless Receiver... check if you have any magnets nearby

I kept getting random disconnects and couldn't figure out why. Until one day i finally happened to move a magnet near the receiver and saw the mouse instantly disconnect. Ever since I stopped putting magnets near it I've stopped having problems.

The magnet I didn't realise was causing problems was the MagSafe wallet I stick on to the back of my iPhone...