I know what you mean re. strimmers. I have had two hogs in the past which came to my garden with bad strimmer injuries. The first had to be put down by a vet. The second survived, but only by spending months at a wildlife hospital with the dedicated care of the people there. Despite her surviving that was inevitably a serious break in her normal development which obviously impacted her life. Needless to say, I hate the sound of strimmers!
Realistically, people are not going to stop using them, but if they took a bit more care, i.e. checking for hogs and other animals first, in an area to be strimmed or even mown, that would be helpful and could save lives.
If you go to ‘My Hedgehog Street’, there are some posters there (click on ‘My Hedgehog Street’ above right and then ‘Free downloadable resources’). There are also various posters on the BHPS site (click on the BHPS logo at the top of this page, then click on information and there is a dropdown list of posters and leaflets). Well worth a look.
Good luck and happy hog watching.