Have had similar symptoms, a bit of a groan from the starter motor and then nothing but the clicks. I have gone over the entire electrical system and cleaned all the contacts, checked grounds, checked fuses, swapped relays etc but still nothing. So I pulled the starter motor yesterday and . . . see if you can spot where the missing bolt should be.
So much groaning from me. I have stripped and cleaned the starter motor, replaced the bolt, added a little grease and been generally nice to it, but it is clear there has been some cooking going on in here - that classic smell of burnt out electric motors. On reassembly I get the same low groan then clicks. Do you guys think it is worth replacing brushes or is the starter toast ? I have a brand new battery BTW. The starter is the original. 2002 sport.