Our parish council have recently changed the rules and have decided that we are allowed sheds. As there is no water available I was worried about how I would collect rainwater without a shed/guttering etc. Apparently before I arrived lots of people on the allotment, like you, wanted a shed for toilet/tools/water reasons so the council decided to alter the rules just in time for us new allotment holders to benefit.

Anyway, the upshot is that I am the first person to get a shed on our allotments, and it looks fabulous!!! I've been an allotment holder for a whole EIGHT days and had a shed after SIX! I got mine on our local freecycle so didn't even pay for it (other than sweat, backache and grunts, of course, oh and a box of eggs from our chooks which I gave to the kind lady who donated her shed!).

It sounds to me as though you have a good case to put to the parish council if the only reason they have is because it's always been that way. Best of luck! I LOVE my shed!