Hi all, we have just acquired a 2010 Meriva B SE. Came with the gunk and compressor - so have obtained a space saver spare wheel and jack kit. Have just picked up the recommended wheel mounting bolt (GM 13345728) and wing nut (GM 90159129) - but am puzzled how to fit to the recess. The bolt is threaded at the bottom - but I can't see what to? Any help gladly received.