Answer

We do not normally supply spares for microscopes, but we may be able to get certain spares for the more popular microscopes, notably for the Motic brand.
Otherwise, you would probably need to contact a microscope service and repair centre such as L J Smith & Son - www.microscope-repairs.co.uk or Harding Scientific Instruments - http://www.hardingsi.co.uk/ etc. CLEAPSS also list a number of other companies who repair microscopes - on their document PS042, Repair and service agents for microscopes. Presumably some of these will be able to supply spares.