For <£400 it would have to be the GTX 1070.
If you can get a 980 for a good £100-150 less then that is also an option.
I went for the 1070 but I mainly use the PC for VR so that seemed the logical choice.
Hey you!! Anti-Chav here!!
Anyway, yeah...
My previous experience in being a systems builder, I'm leaning towards this card due to the customer service etc.
I can stretch to the £430 just... But no more.