Oh Steve, that sounds absolutely idyllic! And very similar to our last house, with an acre of garden beside farmer's fields, with only a shallow ditch separating it. I too used to let wild weeds/plants thrive in one corner to encourage bees etc. And despite the molehills (which my ride-on mower flattened back down) we loved it all. We had fallow deer crossing the ditch and stretching up to eat the blossom from the fruit trees (it used to be an orchard apparently) and foxes, badgers, bats, all sorts of delightful creatures arrived often.
You're quite right, nature sorts itself out, and leaving it in peace keeps a balance in a garden.
However, I sold the property eventually and we bought this little bungalow in a nice village. I feel less isolated, and village life is very pleasant. There are muntjac deer around, a lovely red kite soaring in the sky and the local beekeeper sometimes has swarms which clump in people's gardens and he collects them up with a skep and a smoker.
I do like 'varmints', living things fascinate me. I just wish I could conquer this arachnophobia. and now that my husband lives elsewhere, I must cope with the brutes by myself. Gulp!