I posted a similar wanted ad a few months back, but I still have had no joy in finding what I want - although I do know sizes etc now :)
I'm after a 8ft x 4ft plastic shed. I'm keeping a motorbike in it (7ft long from wheel to wheel), so it needs to be 8ft long & 4ft wide.
Been everywhere this weekend trying to find one without any joy.
Need it to have a base (plastic if possible), and no more than £400 !
Something on the lines of this (but obviously longer)http://www.argos.co.uk/wcsstore/argos/images/7052398SPA65UC260663T.jpg