Purchasing a second hand Laptop, Alienware MX Series?

Hello there, So I'm a little bit strapped for cash at the moment and I need a cheapish gaming Laptop for my travels in which I will be doing a fair amount of soon.

Problem being that I can only afford to spend around £350 on one, And I don't really have much time to get any more together as the whole travelling thing kinda caught me by surprise. Im sure as hell that I cannot get anything brand new for that price. I don't even expect anything good even second hand at that price, But I'd like something that can run a few games while Im not home.

I've been looking on sites such as Gumtree, eBay ect and I've seen a fair amount of Alienware MX11 / MX15's / MX17's selling for around my price range, Would these machines be sufficient enough to cover what I need? I'm aware that they're older gaming Laptops, But I wouldn't need anything that needs to run AAA Titles on Ultra settings, Just something that could Run Rocket League, Bit of Arma 2, Possibly a bit of Arma 3 and Rust.

Current Machine I've got my eye on -

Intel Core i7 CPU - Q720 @ 1.60GHz
AMD (ATI) FirePro M8900 (FireGL) Mobility Pro Graphics Card with 2GB RAM
16GB DDR3 RAM
320GB HDD

If not, Anybody have any Gaming Laptops models that I could search up and pick up second hand possibly?

Thanks for any help.