Boots,
Welcome to Beoworld !
The Beocenter 5000 is actually one of the rarer machines, lovely and superb build and quality.
I can't help you with the turntable dustcover but I have a few brand new original hinge pieces in stock, they always break where they grip into the aluminum lid if forced to close to fast. I can also supply belts for the turntable and tapedeck sections but I suppose they are still fine in your machine. PM me for details. A dustcover from a Beocenter 7000 or 7002 will also fit but some has the model name printed on the rearmost metal part, not that it matter much regarding functionality.
A capacitor kit is also available but probably not seriously needed if everything works as-is.
Martin