Just read the labels and if you have to buy pre prepared foods then choose wisely.
You gave a few examples
I don't see that any proper cheddar (or indeed any properly made cheese) has anything more than a tiny amount of carbs from the milk it's made from. Certainly no added sugar.
Bread varies but you can certainly find some, even from the the big manufacturers, with no sugar in the ingredients list (eg Warburtons stoneground and I'm sure it's not the only one )
Even the worst UK Bread is nothing like the sugary American bread. If you buy heavily seeded breads then they will be lower in GI and also %carbs which may be more important than small amounts of sugar. (even many homemade bread recipes call for a teaspoonful to activate the yeast)
Pate will vary because it covers a multitude of products, there are certainly pates with very little apart from meat and seasoning but obviously they will cost a lot more than products with lots of filler.
Finally baked beans traditionally contain sugar. You can buy them with lower sugar if you want but without any sugar they don't taste anything like the same.
I live in France and none of the tinned beans in tomato contain any sugar (just white beans, tomato , garlic, herbs and salt). They are an entirely different product but most supermarkets have a little English section which always has tins of baked beans; it is the one product most Brits seem to miss :lol:
Even though I live in France, I spend some time each year catering for my father in the UK. I don't actually buy very differently in the 2 countries because I buy very little made in a factory. In neither country do I see a need for any special diabetic products.