My recommendation would depend somewhat on how much (and what kind) of gaming you intend to do. If you want that capacity, you should build the specs to the most intensive thing you want to do. Essentially you would be building a gaming PC in an HTPC case. If you really won't be doing much gaming, then with the current build you will be wasting a lot of power and your specs will be overkill. You could get a much cheaper and more efficient system if you would build this strictly as HTPC, e.g. around i3 or Pentium/Celeron. It seems like the build that you have now is trying to split the difference, but you have specs that will not be all that great for gaming, but will be wasting a lot of energy if it is being used mostly as HTPC.
Also keep in mind, for the HTPC case you will be limited to "slim" video cards.
This would save you about 40 pounds and increase your efficiency by about 45 watts, but you would not be able to do much, if any, gaming.
Alternatively, if you really wanted to do gaming, I would build a gaming PC and connect it to your TV.
PCPartPicker part list:
http://uk.pcpartpicker.com/p/TOHV
Price breakdown by merchant: http://uk.pcpartpicker.com/p/TOHV/by_merchant/
Benchmarks: http://uk.pcpartpicker.com/p/TOHV/benchmarks/
CPU: Intel Celeron G1610 2.6GHz Dual-Core Processor (£32.99 @ Ebuyer)
Motherboard: ASRock H77M Micro ATX LGA1155 Motherboard (£61.49 @ Ebuyer)
Memory: Corsair Vengeance 4GB (2 x 2GB) DDR3-1600 Memory (£20.43 @ Dabs)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£43.13 @ Aria PC)
Case: Silverstone ML03B HTPC Case
Power Supply: Corsair Builder 430W 80 PLUS Certified ATX12V Power Supply (£34.50 @ Ebuyer)
Optical Drive: Lite-On iHOS104-06 Blu-Ray/DVD/CD Drive (£21.99 @ Ebuyer)
Total: £214.53
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-04-29 16:49 BST+0100)