Ok, so unvented hot water, good. DO you really need double basin? If not, I would maybe think about moving the toilet next to a smaller basin on the right hand side of the room as you walk in. I like the fact that both rooms can access the space via the hall way, but you could make the room bigger by getting rid of the hallway and making it true jack and jill with 2 doors into the room lockable on both sides for privacy. Maybe you could then incorporate the space to the side of the stairs if this isn't too sloped. You could maybe then get a bath and a seperate shower in the bit next to the staircase?? Bath could be on right hand side of door, loo in current position and basin to the left of the current door. Difficult to tell exactly without elevations??

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Hi firstly many many years ago certain local authorities would require permission for hip to gables and others wouldn't . I personally took it upon myself to make it a level playing field and ideally make it permitted development (pd) . Many letters ( no emails then ) and phone calls later someone saw the light and they made it pd . Unless the hip directly over looks a highway or your in a conservation area ? to answer your main quirery. besides that I can't see why your loft is not possible and very rarely do we have to take a full bedroom to get the stairs up there. I think I'd have to see the right move listing to get a better feel for you description of different levels . Hard to get a feel but this is one of my last hip to gables. I personally would talk to loft convertors before an architect too. Thanks woody Apex lofts Barnsley "The original roof lift loft conversion company"

Personally I think you need to check the planners view on making the existing loft bigger with either dormers or changing the hipped roof. If budget is an issue I suspect you won’t find moving the stairs to the loft cost effective. But you can likely make the landing lighter by addition a velux at the very top of the stairs. To gain additional accommodation the loft seems like the most cost effective solution but you could also extend over the sun terrace.