I need a fence to keep animals and spotters off the runway; they could be a bigger hazard than the fence and there's also the health & safety aspect to consider..
If you mean farm animals then fair dos:
However you will not keep dog walkers, horseriders, kite flyers, chavs in Astras, Muntjack deer and a whole lot of other stuff off your strip. (I'm speaking from personal experience here).
Our strip is 18yds wide for one third of its length and 40 yards wide for the rest totalling 6 of your great british acres in area.It has unlimited approaches lying as it does along the line of an ex WW2 airfield long since returned to farmland.
Apart from a 150 m stand of trees 20 ft high immediately adjacent to the narrow bit there are absolutely no fences /obstructions indeed the farmer ploughs/drills right up to the edge of the strip on one side.
Presumably the land you're talking about is your own or you'd realise that a 30M wide 'no mans land' on either side would more than double your land rental. (Well it would in our case).
We have two prominent signs inviting folks to ''keep off /active airstrip." Sadly the Muntjack can't read but a low pass (not below 500ft ) sorts that out.
If you've got farm animals a (frangible) electric fence would be safer.
Cusco