UK DIY. Can anyone help me understand why this complex arrangements of wires are connected this way from these two seperate meters

[Kidsolo]

It definitely needs someone to look at it, but I don't think it is as bad as people are making out.
That earth bar (furtherest away) needs two screws holding the wires down.
A door on the whole cabinet would make a nice touch.

 

[westward10]

From what I can see the consumer unit with no lid is using the earth bar as a neutral bar and the right side neutral bar is being used as an apparent earth bar with no earthing conductor to it.

 

[Kidsolo]

an apparent earth bar with no earthing conductor to it.

it has an earth. The last wire on the right goes back to the large two screw connector. If they are going to use it as an earth bar they need a bigger earth wire back to the connector.

 

[Strima]

it has an earth. The last wire on the right goes back to the large two screw connector. If they are going to use it as an earth bar they need a bigger earth wire back to the connector.

The earthing connections on this installation are not suitable. There's no guarantee that the jumpers used to interconnect the CPCs to the main earth conductor will be suitably sized to perform as intended under fault conditions.

Without full inspection & testing being carried out we can only comment on what is visible in the pictures and speculate the rest.