Here are several proven components that complement one another nicely.
Be Quiet! Pure Power 350W MSI B150M Mortar i5-6500 Actic Freezer 7 Pro rev. 2 Crucial Ballistix Sport LT 16GB Kit (8GBx2) DDR4
= 356 GBP altogether. One pound-a-day deal
The machine will be very quiet, lean, and for home use actually somewhat too fast. Skylake makes it re-sellable 5 years down the road and also you want that for the integrated graphics improved over Haswell (refresh) architecture.
Storage and case not included, as you will be using the ones you already have I suppose. For a new built these would do really well:
https://www.amazon.co.uk/Kingston-Te...rds=v300+240gb
https://www.amazon.co.uk/Samsung-Spi...inpoint+M8+1tb
https://www.amazon.co.uk/Cooler-Mast...s=silencio+352