Whilst the GT540M graphics, in that laptop, are reasonable, generally, it has very limited gaming capabilities.
If you want decent gaming, in a 17" laptop, you are probably talking well in excess of £1000. If you can accept 15.6", Novatech has a couple of "gaming laptops", at comparable prices, using the new GT650M graphics, which are supposed to be reasonably good. Novatech don't include operating system, in their base prices, so you need to add that.
Bear in mind, unless you spend a substantial ammount on a "gaming laptop", it's performance is going to be limited, compared to a somewhat cheaper PC.