How can I repair my Kenwood mixer FB370?

My Kenwood mini food mixer FB370 seems to have a broken belt: its motor runs, to judge by the sound, but the spindle does not turn, and the cunning design has kept me from opening the base so far, although I've bought the security screwdriver and removed the screws. I also removed a dirt cover from the base of the spindle, but this did not help open it. I know I can buy the new belt for a fiver or so. Can anyone help?