OP, you said: "it's not that bad - just boring and unfulfilling, have to drive everywhere, no culture etc etc"
Might I suggest that living somewhere more rural isn't the issue, it's merely the rural you went to! I live in what is considered a rural part of the country - Gloucestershire - and I live 5 miles from the nearest sizeable town (Cheltenham) which has more culture than you could possibly shake a stick at: two theatres, two cinemas, a literature festival, a jazz festival, a folk festival, a classical music festival, a science festival, you name it. It's fabulous for kids as well as adults. Where I live I have buses that run until 23.30 most nights and until 03.30 on Friday and Saturday nights. Where I live I am surrounded by green fields.
Transport links are generally good and you can be in Oxford, Bristol, Birmingham, Cardiff, Stratford on Avon (for more culture), Swindon (no culture at all) within, or just over, one hour.
Having worked in London for many years, I love visiting but would hate to live there. I second the earlier suggestion of moving nearer to London but to somewhere where there is more going on. Oxford is a city but you never feel like you're living in one, the rail links to London are fabulous (for your DH's commute), there is tonnes of culture, great museums, countryside on your doorstep? Best of both worlds.