The machine gun must shoot through the fence
{F4918091}
There is still one more defensive structure missing, which would be close to the main tent and which the defenders could occupy in case of an attack from the south.
{F4918107}
It might just be worth moving the machine gun point.
Like this
{F4918124}
This structure is perfectly located, as the defenders can retreat into the bushes and leave the danger zone.
{F4918115}