It'll affect freshers quite a lot as most of it is bonding with flatmates, you might end up hanging out with some coursemates but not nearly as much and societies don't really meet until the first or more likely second week of term.
For social life as a whole, you'll find everything a bit more inconvenient as you'll likely have to make a bigger trek to any meeting place. You'll also miss out on a few house parties.
On the matter of other effects, if you're commuting quite far it will really tire you out and consider that commuting to London is rather expensive and it may work out cheaper to go to and stay at a non London uni.