Thanks for the comments guys, looks like they may be from the crown in the diff, have the matter in hand, thanks again.

Hi all, today I changed the oil in the diffs on my Jimny Alto Hatchback, 2005, the first time since buying the vehicle 2 years ago and which has now got 70,000 kilometers clocked. Upon removing the drain plug to the front diff, two sheared 11mm bolt heads also fell out. I've attached a picture of th...