There is no way that fire is installed correctly.
It looks like that has been cobbled into an old gas fire surround, the flues are not compatable
and rear flies should have a maximum of 6” of horizontal glue before a bend, that definatley looks longer from your photo.
Solid flued appliances must only be installed by a Hetas registered engineer and can be just as dangerous as gas appliances.
I would not touch it at all.
It looks like that has been cobbled into an old gas fire surround, the flues are not compatable
and rear flies should have a maximum of 6” of horizontal glue before a bend, that definatley looks longer from your photo.
Solid flued appliances must only be installed by a Hetas registered engineer and can be just as dangerous as gas appliances.
I would not touch it at all.