Cannock Chase District Council states that listed building controls "apply to all works, both internal and external, that would affect the building's special interest", and names "replacing windows and doors" first among its "Examples of work which may need consent". It adds that "Consent is not normally required for repairs providing they do not affect the building's special interest, but this must be assessed in each case", and records "There are 70 listed buildings in the District, 7 listed at Grade II*, the remainder Grade II."
On conservation areas the council states that "If your property or land ownership lies within a conservation area you should seek Conservation advice before undertaking any development or alterations", that there are "stricter controls over minor development", and that "The cumulative impact of many minor alterations to individual properties, such as replacement of windows and doors in artificial materials and non traditional designs, recovering of roofs and removal of chimneys, can have this effect." It also states that "Conservation Area designation does not mean that no alterations will be permitted."
The Planning Portal states that "An external window or door is a 'controlled fitting' under the Building Regulations" and that "Since 1 April 2002 building regulations have applied to all replacement glazing". It gives two routes: "an installer registered with the relevant competent person scheme", who provides a certificate on completion, or an unregistered installer or do it yourself, "in which case approval can be sought from the relevant Building Control Body". GOV.UK names Blue Flame Certification, CERTASS, Certsure, Fensa, NAPIT and ASSURE for replacement windows and doors in existing dwellings.
We would explain how you check the conservation boundary, any Article 4 direction and the proposed work before confirming whether permission is needed, and put the council's own sentence about seeking conservation advice on the same page.