Yes to both of those questions! If you buy the horizontal package deal from The Intergas Shop, it comes with the rear spacer frame - theintergasshop.co.uk/intergas-rapid/264-54-intergas-rapid-25-plus-049937.html#/32-intergas_rapid-horizontal_flue_kit_deal
Is the flue central ? , Does it need a spacer bracket to keep the elbow out of the wall ?
Yes to both of those questions! If you buy the horizontal package deal from The Intergas Shop, it comes with the rear spacer frame - theintergasshop.co.uk/intergas-rapid/264-54-intergas-rapid-25-plus-049937.html#/32-intergas_rapid-horizontal_flue_kit_deal