We had a new boiler put in last year. 1 thing the engineer said was have your heating on for 30 mins then off for 30 mins. Said you wouldn't notice the difference In heat, but save a bit on the bills. Just get the room up to the temp you want then 30 on 30 off.
We did actually try it and to be fair he was right. We just didn't notice any difference in temp.
Then in the night, have it off for a few hours. Put it back on an hour or so before you are supposed to get up.
Not seen it mentioned. But get a high tog duvet for downstairs. Especially for the autumn. For those days/evenings that are a bit chilly. But you could do without the heating.
If you don't need the heating on, don't put it on. 16oc in the house. Put a jumper/hoody on. You would have one on outside and still be perfectly fine, so why not indoors?
Get a fleece jacket, stick it on.
Bleed your radiator's. Also, do you need every radiator on? Are there rooms where you can just close the door on them and forget all about them? Really need the one in the bathroom on?
The biggest one for us this year especially since spring, has been shutting off the boiler and only turning it on when needed. We shower most of the time at the gym. Not a member? Become one. Plenty of cheap gyms around. We pay £15 a month each. Yeah we use the gym, but £30 a month between us to not have to heat water, is an investment.
Doing the above has meant in the last year we have run up a £1400 current surplus. We have no intention of changing anything. Reckon we can come through this ok with continuing the above and using that surplus.
Other stuff
Don't put lights on when going to the bathroom. Use your phone screen to see where you are going. A bit Boris kettle that one, but seriously, you only need to see where you are going, you don't need the house illuminated to do business. Most likely your taking the phone with you anyway, so point the screen where you are going. You will see just fine.
Batch cook. Do a ton of rice, portion and freeze it. Same for Mash. Jacket spuds. Cook a load off in one go, freeze those bad boys.
Chilli, curry, bolognaise, sheaprds pies, etc. Maybe have 1 night where you cook a ton, freeze it. Your good for the week.
One thing that has helped with food wastage, is a pie maker.
Little bit left over, but not enough for a meal. Stick it in the pie. We have chucked everything in the pie. Curry, chilli, Chinese curry, sausage and beans