Worth bearing in mind that Castleton is in a conservation area, so you may need planning permission to re-clad the roof.https://www.peakdistrict.gov.uk/looking-after/living-and-working/your-community/conservation-areas
It would certainly be worth investigating this before buying any materials as planning officers can be hard work, particularly if you get off to a bad start...
The best approach is probably to speak to the conservation officer who covers the area and get their view on what sort of thing might be acceptable. Technically, they will want to charge you for a pre-app consultation for this, but you might find that they are just pleased you want to talk to them and have an off-record discussion for free. Once you know the sort of thing they will accept, choose your preferred product and provide a sample with the planning app and hopefully they will accept it.
I doubt that they will be interested in the construction details (unless it's listed), it will be the appearance that they care about, but you might still be able to blag anything as an improvement