I'd have thought that even self employed people have a responsibility to notify H&S of anything under RIDDOR.
Example 1 :- Your a self employed subcontractor on a building site and you develop Leptospirosis. (Weils disease) caused by allowing water contaminated with rat urine coming into contact with broken skin.
Would you just have a couple of weeks off and say nothing, knowing that others could be at risk?
Example 2 :- Your a self employed Cabinet maker with a small workshop. Your sharpening some chisels at the grindstone one day and the grinding wheel bursts, causing you sever injuries and unable to work for a few months.
You try to claim off your insurance and they ask if you have notified the H&S of a dangerous occurrence. You answer No... Do the insurance company have to pay you anything?