Question - Possible bunker find?

[vegan420]

Hey I found these the otherday I wonder if there's a bunker underneath?

The top section bolted on seems to be blocked and sounds hollow in the pipe below that ?

Air shaft?

Sealed with concrete?

Two concrete walls running parallel and filled in in the middle? Possible steps leading down?

 

[Speed]

Septic tank?

 

[vegan420]

There's a sewage facility at the bottom of the hill about a good football pitch away, I found this close to the shaft looking thing seems to be a drain or something so could be sewage related I guess

 

[vegan420]