I'm assuming you can buy these from the UK, but I would recommend checking out the Lenovo or Dell outlet. I have snagged a few deals there for myself and friends/family. I kind of frown on anything Apple unless you like the OS/ecosystem because essentially they're overpriced Intel computers that happen to run OS X. Granted they do sort of hold their value, but not if you keep it for 4 years. You can buy a Windows PC with the same specs for half the price. I'm not sure what the exchange rate is, but I don't think you can get a new macbook for $700 USD.
http://outlet.lenovo.com
If you want something that is about 3 years old, you can check out refurbished computers from various online retailers. My only problem with these is I know what the "refurbishment" process is, and basically they wipe the computer down with cleaning wipes and sell it. So the previous owner could have treated it like shit and the cosmetic appearance will be less than desirable. They are typically sold with a grade so you will know what to expect, but you won't know for sure until it shows up. Also these generally have no warranty so if that's important I would buy new from the outlet stores.
Here's some examples of what I found on the outlet right now with similar specs to what you mentioned:
$560
Processor:
Intel® Core™ i5-7300U Processor (3M Cache, up to 3.50 GHz)
Operating System:
Windows 10 Professional 64 - English
Memory:
8GB 1866MHz LPDDR3 / soldered to systemboard
Hard Drive:
256GB Solid State Drive M.2, Serial ATA3
Warranty:
1 Year Standard Depot Warranty
Graphics:
Intel® HD Graphics 620
Battery:
3 Cell Li-Polymer Battery (57Whr)
http://outlet.lenovo.com
If you want something that is about 3 years old, you can check out refurbished computers from various online retailers. My only problem with these is I know what the "refurbishment" process is, and basically they wipe the computer down with cleaning wipes and sell it. So the previous owner could have treated it like shit and the cosmetic appearance will be less than desirable. They are typically sold with a grade so you will know what to expect, but you won't know for sure until it shows up. Also these generally have no warranty so if that's important I would buy new from the outlet stores.
Here's some examples of what I found on the outlet right now with similar specs to what you mentioned:
$560
Processor:
Intel® Core™ i5-7300U Processor (3M Cache, up to 3.50 GHz)
Operating System:
Windows 10 Professional 64 - English
Memory:
8GB 1866MHz LPDDR3 / soldered to systemboard
Hard Drive:
256GB Solid State Drive M.2, Serial ATA3
Warranty:
1 Year Standard Depot Warranty
Graphics:
Intel® HD Graphics 620
Battery:
3 Cell Li-Polymer Battery (57Whr)