Before getting into into the few practical rules that we use here, it is worth pointing out that we are not trying to reproduce nature in any way. Our position about biotopes is a cosmopolitan one; we accept that they change and that foreign plants have and will arrive and settle here. So we see no issue in keeping exotic plants whether they arrived by themselves or we brought them. The rule is that they have to fend for themselves. Annuals & biennials must be able to self seed, perennials must be able to reproduce. They have to be tough; they must be able to survive without watering and spraying.
Because our enjoyment of this place is also created by the fauna, we wish to have the widest range of plants which all will be food for some insect or animal. This includes those who are usually considered as pests like nettle and brambles. Once you have walked through a cloud of butterflies in a meadow and understand that the caterpillars usually breed on a single species of plant, you develop a tolerant eye towards "weeds".
Although we feel good about supporting wild plants that have disappeared in the farmed fields around, we must admit that our main driver is the inherent beauty of a biodiverse landscape. Yes it can be messy, especially in the late summer, but it offers more to experience than any garden and the chaos itself is beautiful.
The first thing to leave at the door is the delusion of control; yes you can influence the development but you cannot plan what will happen.
Since we have inherited this land, it has already changed and we are excited by the prospect that the landscape will change and evolve.
We are aiming to be lazy; we aim to set a balance that will require as little involvement as possible. Time is better spend looking and understanding.