Mice in the bonnet insulation how to avoid

Just a quick one here as some know I am in the middle of rebuilding the engine so am also doing loads of little niggly jobs from headlights to roof lining to diffs out anyway last winter I snapped the washer jet under the bonnet by leaving the battery cover in the wrong place anyway bought a replacement but not the right on and subsequently had a water leak through the hole in the bonnet as it didnt seal properly this leak allowed water to seep between the bonnet and the insulation causing a sag and eventually a hole by the top of the fan and voila a nice home for mice so if you bust the washer jet get a proper one saves on getting rid of mice

:hysterically_laughi