if i knew you wanted to go over 300£ budget i would have suggested Fury Nano for 350£ , way better deal than 390X but 50£ over your budget
mobo i would just wait a bit then upgrade to skylake or Zen with DDR4 mobo, and SSD no need to get 1T, start with 250 or 500Go, install your OS on it, and few games you play most (online games mostly for me) and if you need extra space add anoher SSD
Great advice!
Never heard of the nano before, does it outperform the 390? I managed to find a 390 for £265