For what you're using it for I'd say a g3258 and a 750ti or similar. It will cost less than an i5 alone.
£150 for those 2 you mention. £150 for a Intel Core i5 6400 Skylake
For what you're using it for I'd say a g3258 and a 750ti or similar. It will cost less than an i5 alone.
How about a Antec ISK-310 Mini-ITX
The Broadwell i5's GT3e is significantly faster though.
Really need Intel to get a Skylake part out there with top end graphics option.
https://www.overclockers.co.uk/showproduct.php?prodid=CP-577-IN&groupid=701&catid=6&subcat=567
It's expensive, but it's 65w with Iris Pro... Not sure if there are any Skylake parts with that yet.
You'd mentioned you would have been happy with using an old Bulldozer FX4 chip, so do you really need the performance of an i5? Could save money and just opt for an i3 based Skylake?
Or again, go the FM2+ route with a 7850K for under £100.
If money was no concern at all, right now I'd buy the 65w Broadwell i5 for a low power ITX gaming PC.
Ok, let's make it simple.
Option 1:
Zotac Magnus EN970, ~£570
Corsair Vengeance LV SO-DIMM 2x4GB, DDR3L-1600, ~£35
Your old SSD, £0
Total: £605
Option 2:
Raijintek Metis, ~£35 or Streacom FC8 Alpha, ~£110
AMD A10-7800, ~£90
picoPSU 120W + 120W brick, ~£50
Gigabyte GA-F2A88XN-WIFI, ~£70
G.Skill Ares 2x4GB DDR3-2133, ~£50
Your old SSD, £0
Total: £295-370
Edit:
Forgot to mention that someone else can represent more direct solutions for Intel ITX systems.
And like I said earlier, I would personally opt for the first option (EN970).