PCIe 3.0 is completely irrelevant to you - PCIe 2.0 is still more than enough bandwidth for any video card today, and the Pentium G630 doesn't even have a PCIe 3.0 controller. I don't think any motherboard in that price range is really going to have anything compelling over another (except for extra PCIe slots; not sure whether or not you'd need them), so I'd simply go with what's affordable, like this ASRock H61M-DGS
for £39.56 (not sure if that includes VAT or anything like that).
Also, the 650ti is not
better than the 7850 by any stretch of the imagination.