Well you've picked some pretty ok stuff, but you might be able to squeeze something a bit better from your budget with some slightly better component choice.
CPU - You're probably right about the CPU. HT probably isn't that big a deal, and the Pentium actually has a far better price/performance ratio. since the death of P4 Intel kept the pentium around as a recognisable brand for budget Core derivatives. They used to have far less cache, which is what really crippled them. These days the only real difference is the lack of hardware virtualisation support (irrelevant), HT (less irrelevant than it used to be, but not a killer), and no "turbo boost", ie when only a single core is loaded and provided the thermals are ok the i3 will overclock itself, which is where any actual performance difference comes from. If it's in budget then yeah, may as well grab it; but yes, the differences between the whole range aren't really all that great, a few 100MHz here and there.
Motherboard - your choice is the B85 chipset, which is the budget business option. It's feature restricted as the budget option, which is fine, but you're still paying more for 'business' targeted stuff you won't use (iSIPP, vPro). The budget "home" option is H81. It's restrictions are primarily only allowing 1 DIMM per channel (ie the board will only have two slots, not 4, limiting future expansion), No SLI/crossfire (irrelevant), no Smartresponse (irrelevant), Rapid Storage (irrelevant) only 2 USB3.0 ports (hardly a big deal?), only 2x6Gbps SATA ports (hardly an issue and there's still up to 4 SATA 300 ports)... so tbh that might be a better option for you as it might save you nearly 20 quid:
ASUS H81M-C - £38.00
Only 2 DIMMs is perhaps a shame, but I can't see being stuck with "only" 8GB being an issue
RAM - Yeah.. corsair/crucial, maybe kingston, and it'll be fine. Other than that it's all much the same with different coloured flames painted on.
HDD - You haven't got a lot of choice within budget, but bear in mind the Green series drives are slower than normal as they rotate slower than 7200rpm. They're great for cheap low-power storage, but can be painful as a main OS drive. If you might be thinking of putting an SSD in there when you can afford it then it could be a stopgap, but it's going to drag the entire system down with it. Something like
this might be better, or even have a look at one of the
hybrids - if you save on the motherboard you could afford this and more than any other component the mass storage will determine how responsive the entire system is. It's not an SSD but it's still miles ahead of a normal drive.
Monitor - if you're not bothered about the HDD, saving on the board could let you grab a 24" screen
GPU - The 7750 is probably the best you'll be able to fit in budget; faster and cheaper than the rebrandy R7 250; cheaper than the GT 650.
Also, shop around - ebuyer is cheaper on every single item and it adds up. Here's what I came up with:
Core i3 4130 - £85.008GB Corsair - £63.12ASUS H81M-C - £38.00Samsung DVD-+RW - £11.987750 2GB - £69.34 (this is the one item that costs more, but it is the 2GB version)
Cheapy case+PSU - £21.99Philips 21.5" - £72.99Seagate 1TB/8GB flash hybrid SSHD - £65.46Delivery - free! (if you can wait, though they often get it shipped sooner than 5 days)
Total: £427.89Enough left even for the larger screen maybe?
[Edit:
This board will be absolutely fine too, saves you £3, and AsRock are absolutely fine)