Stripping off the existing cement tiles and existing slates, to replace with new natura…

EXPP: PROTECTED STRUCTURE: 1.Stripping off the existing cement tiles and existing slates, to replace with new natura slates to match original; to note that where possible the original slates will be salvaged 2.Replacement and/or splicing of existing roof timber where required 3.Replacing and/or sistering of the existing timber rafters where required 4.Replacing of existing hip rafters and ridge boards where assessed as undersized or structurally deficient 5.Spray-treat all roof timbers as appropriate. 6.Insertion of new ventilation between rafters to allow for new insulation; ventilation to be type glidevale eaves to the rear roof, and ridge ventilation to front roof. 7;Replacement of highly damaged roofing membrane with new breathable membrane. 8.New breathable insulation at ceiling level. 9.Replacement of the PVC rear gutter and down pipes to rear with cast-iron gutter and down pipes; sizing of gutter to be assessed by the engineer to allow valley rainwater to be caught 9f 10.Assessment of inner valley, and valley gutter outlet to see if replacement/repairs to existing lead is required 11.Repointing and reflaunching of chimneystacks Are the above works considered exempt development?