You guys are fantastic! I think I'm pretty close to it now, a bit more messing around and it should be all good. Just got to remember how I did it so I can repeat it on the real plan. I ended up using a pony wall with the upper section as a shower wall, with a railing, then the beam over the top set to the require dimensions and materials, a moulding polyline for the sill, set the Newels/Posts to zero width also and used a polyline solid for the curvy bit in the corner. Just need to figure out the awning over the top of the window, that should be fairly simple I hope.
Thanks again hopefully I can return the favour to someone sometime.