Firstly a big fat SORRY because I've posted about this god-awful bathroom before (also sorry for the messy picture and the ikea book case which is lumbered in there too) and all responses have been great.. so thanks. After going around in circles with various layouts, I've come to the conclusion that I'd prefer to leave toilet on the wall it's currently on because this is external and saves a lot of work (and money) to move to an internal wall.

My though it to leave sink/toilet on end wall but swap the two. I think maybe a nice large sink/vanity area, possible with a wall hung toilet would look neat and tidy.
Because of this, the bath tub also needs to stay in its current position and unfortunately there's not space for a separate shower area.
As such, here are my questions:
1) leaving bath in its current position, should I replace with a freestanding tub or with a nice tiled built in one? What would look best in that position?
2) I'd need to fit a shower above the tub. If it's a freestanding tub (I think I prefer a freestanding tub) what are my options for shower screens? Sorry I hate shower curtains so want to avoid them
3) finally.... can anyone think of a better layout than this one? Be aware, nothing can go along left hand side (opposite tub) as there's a loft hatch which needs to remain accessible)