If we encounter flystrike I get out the clippers and shear a big circle around the area, moving inwards like a Swiss roll. By the time I get to the maggots there's nowhere for them to hide. I use an old 1 litre washing up liquid bottle with a centimetre of Jeyes fluid in the bottom and filled up with water. Even at this dilution it's enough to irritate the maggots sufficiently to make them leave the skin. Any stronger and it's extremely irritating to broken skin. If your sheep is still nabbing at any part of its body, making sudden small moves, tossing its head, grinding its teeth or unable to settle and graze - you've missed some.