How to fix a leaning rainwater tank?

[23lros23]

We bought our townhouse with a rainwater tank already installed in the courtyard, maybe in the range of 2500litre tank.

The tank has a rotted wooden frame around the outside and the base under the tank appears to be crushed something and not concrete.

Over the years the base has been washed away to now have the tank on a lean (as shown in photos).

Due the recent rain, the lean of the tank doesn't allow the pipes to remain connected or runoff to flow into the tank. The tank is currently full.

There is limited space between the tank and the back fence where the lean is occurring. Any suggestions on how to fix this issue

?Front on water tankBack of tankBase at back of tank near fenceSide of tank base and frameTap into ground water tank and baseShowing lean of tank