Oh dear, oh dear, oh dear. A lot has been going on whilst i've been away for a few days. I've just read 4 pages i think since my last post!
Couple of things i just want to mention, if i can remember it all:
Looks like the starting point over the bath is relative to the window sill? Have no idea why he would start it like this. I don't fancy shaving what looks like about 10mm off the tiles cutting down to the bath. Whilst i think about it, what is the height of the bath? It might be the perspective of the photo but it looks awlfully high. Average bath panel is 20"-21". For sanity purposes just check the height mate.
Think the wall tiles around the bath are going to have to be removed really. Asthetically your going to have, what looks like around 1/3rd of a til to cut to the ceiling (100mm) and your cut to the floor looks about double this. This alone, and as others have stated, doesn't look like a pro has done it. Add about 2" to the height of the top cut and it'll be about right top and bottom. This will however leave a cut under your window sill of the same. Good solid porcelain like you've purchased should cut and fix nice of that size though and won't look out of place.
Someone else has referenced how easy they've come up as well. I've mentioned this on about page 4 prehaps? It is very very surprising to me how you are manahing to lift these so easily and in one piece!
I really hope you get on with your next tiler, if you don't action' i'm going to drive out and do the tiling myself for you (seriously!)
Good luck