what's scary is that you said UK and not US. Coming from other Anglo cultures and going to the US feels similar to what you describe moving from Russia. instant increase in added sugar and serving sizes.
There are plenty of bread recipes that require no sweetener, and it's definitely not needed for yeast to develop.
A lot of the packaged supermarket bread has additives to keep it fresher longer, one of which is sugar. Go either a little upmarket or to the baked-in-store section and you'll find some without it.
Bread has been staple food for millennia. For most of that time, sugar was rare, expensive or totally unavailable.