Hello to all Community Members and thank you for your replies and suggestions. I'll follow the various ideas and see where I get to.
My research so far suggests that the Welsh Government's Open Planet Development guidance and ideas are not welcomed by Planning Departments.
It seems to me that I need to find and buy my land, get some sort of small farming / smallholding activity going, experience the trauma of thefts because I am not resident on site, and then (re)apply for planning permission.
I'm sure there would be a better way to "do" planning, even in these days of protection of the landscape etc, for people who wish to undertake a good contribution to the environment. I'll keep going: I think my goal is good.
Many thanks, and any further comments will be welcome.