The tank sits in the base, the base is bolted to the floor.
As a extra precaution i have also packed timber to any gaps.
The tank is 100% retained,it cant move anywhere.
I showed the guy across the road from me, who is an engineer, he told me that the material used is the very best,infact this is the same material that i used to use on building sites when i was a plumber.
The base was bolted in by the same guy who fitted franks tank