But isn’t it an advantage to have it at rush hour as it would mean less driving
Doesn't work that way. Examiners know which routes to avoid in rush hour and you'll drive as much in rush hour as you would outside of rush hour. In rush hour you're risking commuters, school runs etc. mucking up your test as you need to be ready to react to anything.
Looking at test times at the two Bradford test centres, I'd be going for 10:14 or 11:11 as first preferences.Then probably 13:30 although might get some residual lunchtime traffic.