Should I use the parking brake in driving test and use mirrors more??

So I recently got a new instructor since it wasn't working with the previous one. The new one's car has a parking brake but the instructor said I don't need to use it. I've previously had lessons in a car with a parking brake and used it a lot so I know how to use it but this instructor doesn't want me using it. Do I use it in the test? I feel like I should if there ends up being a long wait somewhere like at traffic light etc. Or should I not use it? If I didn't use it in a situation I should have will I fail the test or get a minor mistake? I don't want to change instructor again as my test is in a couple of weeks so not worth trying to get used to another car when I'm getting used to this one.

Also the instructor doesn't want me looking in the mirrors unless I'm about to do something. Before I was looking every 10 seconds in centre mirror and looking at side mirrors every now and again but the instructor said not to do this, wants me looking straight ahead unless I'm about to do something like turn, switch lanes, change gear etc. Not looking in the mirrors is resulting in car positioning wrong sometimes or I'm missing car behind me or wanting to overtake. I know I'm supposed to look in mirrors as most of the good previous instructors have said I need to look in mirrors more so in the test I will, in the lessons I sneakily look at the centre mirror without moving my head and look at side mirrors when she's not looking which she hasn't noticed. I'm also taking lessons with a different instructor who is really good but doesn't cover the local test centres or the one my test is booked at otherwise I'd do the test with her. There's no tests available anywhere and probably won't be available until next year so at this point can't be changing instructor again this close to my test.