And if they made up 45% of their stories, I imagine their trust would be 0%.

You seem to be looking at the wrong chart. Around ~50% each of each politically leaning group use BBC as their primary news source.

However, 79% of Brits trust the BBC as per this chart:

https://legacy.pewresearch.org/wp-content/uploads/sites/2/20...

That was back in 2017, if I'm reading the chart correctly. A lot has changed since then, so I'd be genuinely curious to see what more recent figures looked like.

Which is a completely different issue. "Do I trust this news network?" is a subjective opinion. Flat out misstating facts and inventing sources is a much more significant problem.

Did you mean the Guardian? Because trust in BBC is at ~80% according to what you linked.