a good start, OP!
oil fired heating; NEVER use direct debit/regular payment systems. Monitor the price (as mentioned it is still dropping) and tank up when it is low. If you need to save up to do that, fine, but save up in your own account, you could even earn a few drops of interest with a current account. If you use the regular payment systems you don't take advantage of price drops, they do. Also shop around for every fill up. The minimum is 500 litres, sometimes buying more works out cheaper but not always. Sometimes there are local co-op schemes to buy in bulk, which may work out cheaper but not always. Be wary of boiler juice etc.
I'm also on oil and electricity, our monthly electricity bill is £27 so welcome to my frugal club. :-)
you mentioned contents insurance; does that mean you are renting so don't pay buildings insurance?
driving style; this is the biggest way to save fuel assuming you aren't in a 3 litre Ferrari.
. First thing is to use the car as little as possible. Second is to combine trips, never go for just one errand. But equally don't drive round the town, park once and walk. Get rid of all unnecessary weight from the car; roof rack off, clutter out of boot. If it has a big tank only fill it half way. Finally, look at how you drive; plan well ahead, don't brake-accelerate-brake, don't overtake unless something is stationary. Don't risk life and fuel overtaking, you WILL only be one car ahead at the next roundabout. On a motorway, left lane and a steady 60mph.
you know what you have to do with food waste. Buy in season, buy what you use. Cook double or more, freeze half. If frozen veg is on offer, buy that; no waste and just as good for you. It is summer; know anyone with a garden or an allotment? They'll have a glut and be glad to help you.
hate to say it, but stop buying new books. Charity shop, fetes, library, kindle for e-library books. Or spend £30 on a second-hand Nook which works with library ebooks and pdfs. Free reading!
don't use savings accounts. If you want some real interest, start with a TSB Classic Plus account which pays 5% on up to £2k. Then add a Santander 123 which pays 3% on up to £20k and gives small cashback on bills, for a £2 a month fee. Both accounts need minimum monthly pay-ins; if salaries are not enough then simply set up a standing order to shift money between them. Don't bother with cash ISAs at the moment, the above accounts pay more even allowing for the tax.