There is usually a 3 for £10 offer on meat at Morrisons/ASDA and probably tesco too, it works out really well and if it's only you eating SW meals they will last you ages. We usually get pork chops and mince, we portion it out and freeze it to use as we need it. Only thing is its never extra lean mince in the offer, just the lean stuff, but when I cook it I drain the fat off, then pour boiling water over it through a sieve and it's basically extra lean! I think it's 3 syns per 100g so it's not that high anyway.
Frozen fruit sometimes works out cheaper too, Tesco have 3 packs for £5 and it will last you forever. One pack of chopped mango lasted me a week just having a small portion with my lunch every day. I portioned it into sandwich bags to defrost as I needed it. Frozen veg is cheap too and usually saves time because it's already chopped! Great for stews, soups, curries, anything you cook for ages basically (not so good for salads or stir fry)
As someone else suggested, pound shops like home bargains or b&m will have lots of SW stuff much cheaper than a supermarket. That's where I get things like smash, tinned tuna, herbs/spices, cereal bars, some tinned veg etc. You'll get your non SW stuff there too for your OH.
Also check the reduced sections in supermarkets. I got about 7 sirloin steaks in there once for about £9! And try Farmfoods or Lidl for muller lights - I've seen them in tesco £2 for 4 which I think is too pricey, whereas Farmfoods have 6 packs cheaper than that.