Cooker Hood fitting and adapting question

[Mike13]

Hi,

As title want to fit a cooker hood, we have a few models we are looking at, but so far the fitting drawing shows that the maximum height that the unit can be fitted is below the minimum allowed for a gas hob.
Are they easy to cut down to a more sensible height?
I know I have some cutting to do as the cooker hob will be on an internal wall, and so I need to make a sideways cover for the duct to carry fume to the outside.

 

[foxhole]

There is no maximum height only minimum . Mounting higher may reduce effectiveness of extract but if you are designing a hood it can help mitigate this to some extent .
I made a unit to suit my kitchen and installed a basic cooker extractor into it .

 

[Mike13]

The hoods we are looking at give a minimum and maximum measure for height from top of chimney to base of extractor.
I require the hood to be higher than the height given by the minumum distance to ceiling.

using that image as an example, many are similar. I need the chimney to be cut down and a side hole cut in for a duct.
The question is about how easy or difficult that is to do neatly.