You might wanna look into this. Besides lower power consumption I don't really see a single reason why you would want to go with i5-7600 when there are cheaper and much more viable options, such as i5-6600K.

Can't really comment on GPU, not a fan of AMD.

Water cooling is fine although for such build you could easily get away with traditional heat sink and save few pounds.

Everything else seems fine to me. One thing you might wanna add is an SSD, even if it's the cheapest one, just to install Windows on it.