Mystery Tank

This bit of work was completed a while ago so I thought I'd share with you pictures of the Mystery Tank under our front garden.  It is MASSIVE!  (About 10 ft cubed.)  It pre-dates the 1951 house, and was full of soil and debris (old carpets, wheelbarrows, rolls of barbed wire, bits of pipe etc, etc decades of rubbish).  Sean's men had a heck of a job cleaning it out but it's now ready to be turned into a water storage unit for use in the new house, eg for toilet flushing (although Hannah's suggestion of creating a shark tank is far more imaginative!).  Adrian's idea of a mechanic's inspection pit (it will be underneath the new garage) was also tempting ...

Any other suggestions???