Here is the final details tohttp://www.gb-online.co.uk/gb-wordpress/?p=1142
There needs to be somewhere for the hottub to sit on. It was deemed that concrete was the best option. So a slab had to be laid, just the right size and thickness, with some steel reinforcing bars embedded in it.
With the concrete cured the hottub was slid on top. Also the thoughts went onto the power cabling side. A new earth electrode had to be fitted adjacent to the hottub, and also the isolator nearby. A cable trench had to be dug back to the house. Depth was an issue due to a large concrete slab being under the ground at a depth of 60cm. All wire armoured cable was installed and certified.
A bit of a pause then for bad weather, as the ground was very sticky clay. Also design time for the next stage. Note how close the decking joists are, and some are doubled, with supporting pillars close together.