how do you know when to straddle lanes going for my license and struggling to when to straddle
As a general rule if you think you need the room use it at least in the real world, it’s better to take up more room and keep others safe and avoid accidents.
As for a test it’s a difficult one but your better getting a minor for using both lanes when it wasn’t necessary rather than a major for not doing so and nearly causing an accident.
Your instructors should be pointing out and places where you need to take both lanes anyway on all the test routes so it’s just remembering where.
Most lanes as long as it is wide enough and you have a fair distance to move forward before turning and generally it won’t be an issue. If the lanes are narrow then yes absolutely useless both lanes.
That’s my take on it anyway I’m sure someone else may be able to give better advice, but listen to what your instructors are telling you as they (should) know what they are on about.
I agree with that.
Asking for written advice on a forum will generate more confusion than help.
Talk to your instructors and ask questions.
if you are on a dual laned A road and be turning right,I’d straddle most of the outer lane to block motorists entering the tail-swing zone