Due to the gale force winds a few weeks ago I had to redo my setup.
I came back from work and the dish which had been left at 13e was on more like 53e

.
There was some play in the pole and the wind turned the dish around on the pole.
Removed the dish and pole and set to work on the hole again. This was no easy task as the old concrete was at the bottom of the hole and took some getting out.
1 bag of concrete mix 2 bags of sharp sand and 1/2 bag of pebbles made some mean motar for the hole. Also added some half bricks and rocks that were lying about the garden. Left all this to set for 2 days and then added 2 bags of post cement over the top for good measure.
Resulting in a pole that is 100% vertical with 0 play and a job that should have been done in the first place.
I have learned the hard way and should have done this on my first attempt.