17mm head on the bolt cant you just get some on ebay?
Edit: Getting alot of M10 results... http://www.ebay.co.uk/sch/i.html?_odkw=b...r&_sacat=0
Edit: Getting alot of M10 results... http://www.ebay.co.uk/sch/i.html?_odkw=b...r&_sacat=0
Doesnt even own a 306.