Replacement roof in a conservation area

[Patricia Baston]

Class C (Town and Country Planning General Permitted Development) (England) order 2015 Schedule 2 Part 1, allows for minor alterations to roofs not involving enlargement, such as a change in materials, on condition that any changes would not materially alter the shape of the dwellinghouse and which includes the removal and replacement of rooftiles.

Would changing black, Marly Eternit concrete tiles with breathable under felt with black natural Welsh slate tiles be permitted development?

Or do you also have to take into account Class B which also covers alteration to the roof and but excludes works within a conservation area?