Cockney Steve
What troubles me is that you seem to have a very strange idea of the price differential between high quality bolts from a commercial source and those standard parts from an aviation source, the fact is given the extra effort to check the suitability of the commercial bolt and the liability ( or lack of ) issues the price differential is very small for the extra quality assurance.
As for the so called freedom of the American experimental scene, it is all very well for those who know what they are doing but it gives the idiots a chance of killing them selfs and any innocent who is unfortunate to fly in the aircraft built by an idiot. I have only once been unfortunate to get involved with an experimental type Imported from the USA, my lasting memory from a string of safety critical defects was the high voltage strobe light wires that passed through the fuel tanks inside a bit of normal garden hose !
This aircraft can't have been typical of most American home built aircraft and may be it got to the UK because all the locals in the USA had the inside information on the builder, but it shows that the LAA quality system is in place for a reason, and works well to keep a check on those who don't have the skill or knowledge to do the job properly.