The soil around this area in Bourne End is chalk and flint, so it could be interesting going. The first 12 inches or so are not too bad going.
Then we hit a very hard layer of chalk about 20 inches down, no way through it.
The only solution is to get a pneumatic drill and drill through it to a depth where we can put in the socket post for the mast.
Line up the socket to vertical and pour first concrete…
Keep filling with concrete. Also putting in the cable duct from the fence line to the base of the mast.
Finally smooth out the concrete and leave to set. The base is a couple of inches below the grass, so will cover it up with some soil and grow the grass back over it.