I was looking back at our bills, and it's obvious from ours that the various improvements have made a huge difference. We did it in this order
a) loft insulation & door curtain for front door. New curtains with thermal linings
b) double glazing & new porch & front door (gives a buffer and the hallway is amazingly so much warmer) Edited to add you will need to talk tothe listed building people, may have to get internal glazing
c) solar. This, when generating more than we are using diverts to heat the hot water. Edited to add this may be more complicated as you are listed.
d) changed boiler for a new Rayburn 680k which works the hot water & heating on timers. Also flushed all the radiators. They're only on about an hour a day max for water (due to solar) and the thermostat means the heating almost never comes on before Christmas/after mid March, and we can turn the Rayburn off completely for hot water for 6 months.
e) Replaced conservatory at back of house with one with better roof (insulated)> This acts as a buffer to keep the back of the house as toasty as the front)
27 years ago we spent over £80 a month on electricity (now £55 at current rates!)
Oil we used 2000 litres a year, now we use less than 500 litres a year (about £55p/litre I hope, waiting for oil price to drop lower). Oil was most expensive circa 2014, just after we changed the boiler luckily.
You could look at cutting the TV subscriptions, certainly there's a limit to how much TV you can watch! We don't subscribe to anything other than a free Amazon prime month every now and then.
You may be able to shop about for a cheaper broadband deal than Gigaclear, but may be tied to a term.
Ditto the phones, that sounds expensive. There are some good deals on at the moment for SIM only - check if you have paid for your phones now and whether the contracts are appropriate.
Baby wipes, can you mostly use flannels esp at home, and wash? Particularly if child is no longer in nappies, loo roll for bums & flannels for hands, take a small squirty travel bottle for out and about.
Trains to work - can you share travel anyhow? Cut down on office days to cut travel costs? My neighbour and another chap down the road take it in turns to drive to the station, and share a car = 1 car in the car park (I think it's about £8 a day), sometimes there's another chap they pick up too.
Cannot do anything about council tax, we also pay similar for a small 4 bed house, but you could look at which band you are in vs similar properties and contest the band you are in if you find evidence of other larger properties in lower bands than you (but they'll likely just put the other properties up that's what they do here)
For food, as you presumably have a nice farmhouse garden, I'd consider growing tubs for the more expensive items eg tomatoes, peppers, cut and come again salad leaves, strawberries, and blueberries. If time, a few rows of other veg (we had some marvellous brussels that went on all winter), carrots, beetroot, beans, peas etc. We picked masses last summer and I have a cupboard full of jams, chutneys, pickled stuff, etc. Good activity with kids. You could consider a few rescue chickens and sell the surplus to pay for the feed, we always more-or-less got free eggs on that basis.