Hi Michelle, While bathrooms are very much my area, exhaust fans aren't as they are installed by an electrician. If you know one (or even perhaps call an electrical wholesaler?), you might be able to ask them what brands are the most reliable (i.e. what doesn't come back for repair/replacement). I did find this really helpful article on line about exhaust fan location, size selection and fresh air ventilation which are crucial to effectiveness: http://www.beaconlighting.com.au/fans/fan-tips/exhaust-fan-tips.html Good luck!

You can have a pull up range hood built in to your bench top. Think Smeg does one called downdraft. They have been out a while, so might be more. Basically you install behind your hot plate and pull it up when your cooking.

contact an electrician and they should be able to find a suitable replacement and also advise about how to cover any gap

Spoke to a afew people and definately not. Managed to get my builder to rectify (he said it was a misunderstanding) but that they would move the ducting so it sits over the exhaust fan