Have you not looked at what your allowed to build without planning permission ?
Is it a conservation area or any other restrictions ?
you could look at temporary structures (with a plastic /polycarb roof)
these don't require planning or br approval if sited away from boundrys and highways.
failing that,talk to the council and ask what you can have ,before any more planning applications.
as reguards "modern clasics" the council will just see them as scrap metal unless they are taxed,moted

sorry but that's just how it is in my experience.
JM2PW