Struggling with noise on bathroom render

Hi guys, I did this scene in Blender 2.77, I set my samples to 1024 and it still looked noisy even after taking over an hour to render on my PC. (i3-4150 with GTX 750Ti ). I tried using portals over the windows and that seems to make little or no difference as far as I can see.
I see some superb renders here with considerably less samples so I have to presume I am doing something fundementally wrong with my lighting.

I have uploaded a stripped down scene to my google drive:

If anyone could take a look at it and outline any changes which would improve noise / render time I am all ears.