Raise roof pitch - works required

clueless_but_curious

I live in a semi-detached bungalow.  Following the amendment to general permitted development within the town and country planning act in Dec 2020, I am considering raising the pitch of my roof which is currently 1.9m and therefore not habitable.  Assuming party wall consent, I'd welcome any thoughts to help me build up a picture of costs to just get the new roof on.
What height would work to increase to for a workable space for bedroom and bathroom?  I have two roofs (owing to a pitched roof permitted development extension to the rear) so would only be proposing to raise the roof of the original house footprint which is c.60 sqm (8.5m x 7m).  I guess there would be two dormers on the front elevation (if allowed) and sky lights to the rear (no requirement for dormers looking over the rear pitched roof)
This is all in my imagination at the moment so I would love any thoughts on what to expect to help me get an idea of cost of just getting the new roof on.  I am looking for some thoughts on:
- Site prep - what is involved?  Remove soffit/fascia, roof tiles, batons.  Pull off ceilings.  How much labour time apprx.?
- Remove roof - just saw apart?
- Install new roof.  Material cost?  Carpentry time apprx?  Any requirement for scaff?
- Staircase (nothing fancy e.g. pine).  Material cost?  Carpentry time apprx?
- Glazing supply and fit for the dormers?
- New ground floor ceilings and skimming

Hope that makes sense!  Really interested in thoughts on height of new roof.  I can do the geometry from there.  I am 6'3" so would like to be able to walk around a king size bed whichever way it is positioned!
Note: ignore roofing (inc insulating), first floor flooring, partitions, plumbing and electrics

DevilDamo

You would not be able to utilise the recent changes to PD so would require formal Planning. Speak to an architect/designer who would start reviewing the existing and then proposed situation. From there, you can look at obtaining some ball park costings.

Not sure how you expect anybody to provide you some initial costings without having a suitably worked out scheme in place.