Gas flue pipe + insulation

[richardrich79]

We have a gas 'Woodburner' like stove & I am in the process of changing the fireplace surround. The actual stove and all fittings are not being touched.
The closure plate has a small inspection hatch for clearing debris that may fall down inside the chimney which I've opened up and cleaned out a small amount of dust.
We had all the flues tested by the gas board however I'm not sure if there should be any insulation in the actual chimney surrounding the stainless gas flue. I know that seems to be common practice nowadays this has been in a while and tested last year.
Is there anything to be gained by sticking some insulation in?

 

[Agile]

Do you have a flue liner all the way to the outside?

Or just a spligot or short length of pipe sticking up the chimney?

If it works fine without insulation then I dont see any point in fitting any.

Tony

 

[richardrich79]

The liner goes all the way up finishing with a cap on the chimney pot.