Following our discussions with the builder, and his conversations with the local authority we have submitted a planning permission request to raise the roof line. This will allow us to move the window up again so that the internal window ledge is at a more acceptable level. If we are able to raise the roof line from that already agreed, it will also simplify the roof structure.
So to recap, this was drawing is of the original house.
This was the first to be given planning position, with the dropped roof line over the extension.
This is the drawing as we have submitted for approval with the high roof line.
The planning permission process includes a public notification period, we therefore will not have a decision until at least 5 weeks, possibly as long as 8 weeks. It is likely the builder may run out of jobs he can complete before the roof needs to be ordered, which can't be done until we have the decision.
It is a bit late in the game to be going through the planning application stage again, but out plan is to live here for the next 20 years so we are prepared to wait a number of weeks rather than live with a compromise for all that time.