The brushes are not shown as a separate part on the LR system, but don't let that stop you asking the local dealer Parts man who they recommend as a local Bosch stockist.
I suggest you read a Bosch number off the actual starter motor and start looking via Bosch stockists.
Their number of the starter motor may help you identify a set from Ebay.
Alternatively use the starter motor part number as a Google Search term (other search engines are available). You can sometimes get results that list not only the starter number but also the parts. Be prepared to go past page 1 of the search results.
HTH