Yeah, you are right.I think you're still missing the point, only real thing you can do is tweak job description to something plausible. Ie accountant to financial advisor say, and see what that can do. Where you keep it, adding named drivers too. Short of that where you live and value of the car are the huge factors, hence why it is pointless comparing what everyone pays.
There's things you can try to make it cheaper.. adding/removing named drivers (parents/spouse etc.), job description.
Try and get the mileage as accurate (but low) as you can, 10>13k mileage I believe made £70 difference for me. My fuel/mileage is logged with an app so I can try and be quite accurate, though I never understand how insurance companies would know if I did 5k or 10k a year... ?
Multi car policies again can help, my insurance is like £700 or something, but without the multicar the cheapest I found was basically double that..neither of my parents can drive the car as it puts the price up. Admiral even let you do multi car between different addresses, so my sister and her partner were on a policy with me and my mum... 4 cars, 2 addresses, 5 drivers.
Things like postcode and stuff obviously you just have to live with. There's no magic way of making insurance cheap, just look around, try and get many quotes and edit the quoutes with mileage/drivers/job and then live with it sadly.