Relocating stairs…

[KM88]

Currently under off on this house and looking to fit in an upstairs shower/wc without the cost of extending the rear of the first floor. Does this stair relocation up to the loft extension look feasible…? It would mean we could use the existing walk way and stair turn to fit in the shower room. 
Am I likely to need to seek permissions for work like this? 
thanks! 

[Dave Jones]

you may not have enough height if the roof is pitched to get the stairs in. You need 2m clear above the nose of every tread.