I have had a go at using a m3 nut, spring steel lock washer and bolt with a loop crimp fitting on the wire (Rapidonline 33-0605)and it seems to be working at the moment. Much more secure than the croc clips and after the testing phase for the GCSE pupils with croc clips they then use the more permanent method to install their designs in the final projects. All removable after the event and re-useable. Also for some pupils much less chance that the components will go walkabouts.
