Gas Fire Issue - Installation Question

Hi all,

We've had a Dru Global 100 Gas fire fitted in an extension recently, we had it on for the first time properly last night (we were told to let the plaster dry on the newly made chimney breast for a few weeks before using the fire). Spec :- Dru Global 100 BF

Issue is the we had the fire set to MAX but it didn't seem to be giving off as much heat as id expected, nor did the flames seem that large either. It's a 7.5kw output (94% efficiency) so thought it'd be really warm... It's got me wondering whether it's just me or if something isn't right, so wanted to ask on here.

One thing i did think of was; I recall during the installation they had to put a couple bends in the flue to avoid a ceiling joist. Am I correct in thinking bends like this will affect the draught and therefore could be causing the fire not to run as big as it could? or totally unrelatable? Photos below. (yes that socket was eliminated )

https://ibb.co/6mH9v5T - installation flue

https://ibb.co/kJXkwLQ - fire on max settings


thoughts on the above? or anything else I could consider looking into?


thanks!

Ged