yep, you are correct.
Welcome to bonkers britain.
I always make sure we purchase a fair amount every year with credit cards for this exact reason, I kid you not. It's fooken laughable that the more debt you have & pay off, the more credit worthy you become in the UK. Totally the opposite of what it should be.
On a similar note though. A 28 year old teacher who has just joined my wifes school as a senior teacher (that alone makes me laugh, senior teacher at 28 ffs ), has just been refused credit for a new mini, he also rents. I don't know his personal situation, but if a senior teacher can't get credit for a mini, then somethings wrong. He opted for that deal where you effectively just rent the car.