New Gas Fire: Fireplace shop suggested an open-face fire but I want a glass-fronted high efficiency.

Adamc

I'm looking to replace this fire with a high efficiency gas fire. We believe there's a brick fireplace behind the drywall.

The house is a dormer which has had a first floor added so there is a class 2 flue surrounded by brick at ground floor level. Then the flue is enclosed in drywall on the first floor, then unenclosed in the attic crawl space. The fireplace shop have said a glass fronted model is not appropriate (this is without visiting just based on these pics).

They suggested another open fronted fire as glass-fronted fires do not go with prefabricated flues(?) but i want max efficiency. Should I give up on the idea of a high efficiency fire or is there some hope? What is the most economical option for my set up please?

Inset fire. Drywall and presumed brick behind.

Flue behind drywall first floor

Flue in attic crawl space

Ectophile

I'd be inclined to get a second opinion from someone who actually visits the place.  A woodburner or multi-fuel stove is a lot more efficient than an open fire.  But they will require the correct type of flue installed, and that's where a HETAS registered installer would be able to tell you for sure.

in_my_wellies

I agree with Ectophile, find a local independent shop. Mine suggested one of these: 
https://www.gr8fires.co.uk/products/mazona-micon-fire-door?variant=42898988368111&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gclid=EAIaIQobChMIsNOh7KziggMVCZGDBx0q5gBMEAQYBiABEgIlq_D_BwE

It' s door which fits in front of the open fire, it works well. Just showing you an alternative to a stove (sorry, not sure if you want wood/coal or gas)