Top corners and returns need appropriate ordinary cutting and fitting. Show any unusual junctions before ordering material. A compatible profile and adequate lengths matter; filling large mismatches is not equivalent to a properly planned replacement surround.
Existing paint, adhesive and fasteners affect how the old surround can be removed. Some surrounding making-good may be needed. The service should not promise damage-free removal from every finish, and any unexpected deterioration needs discussion before the opening is covered again.
Width, thickness and shape affect how the new surround meets the opening and nearby trim. Supply the proposed profile rather than relying on a distant photograph. This is decorative architrave replacement, distinct from repairing the door jamb or load-bearing parts of an opening.
Replace the accepted ordinary decorative surround with suitable joints and fixings, leaving the agreed preparation for finishing. Scope limits: Ordinary decorative surrounds only. No structural jamb or opening modifications, specialist glazing, fire-door certification or hazardous-material disturbance.