Prefab concrete liney new stove

[fabgav]

Hi all.
We are going to get a log burner installed.
The chimney is a pre fab concrete pipes system with 7inch diametertje drive requires 5inch.
We've been advised that we don't need a 5inch Flexi liner as there's not much point as long as the smoke test is okay.

What's anyone's thoughts?
Thanks in advance

 

[Alastairreid]

Your advice is sound, no point lining a liner which holds a test.